{
  "cik": 1370450,
  "cik_padded": "0001370450",
  "entityName": "Willdan Group, Inc.",
  "fiscal_years": [
    {
      "accn": "0001104659-26-020767",
      "filed": "2026-02-27",
      "fiscal_year": 2026,
      "form": "10-K",
      "fundamental_units": {
        "capex": "USD",
        "cash": "USD",
        "cost_of_revenue": "USD",
        "eps_diluted": "USD/shares",
        "free_cash_flow": "USD",
        "gross_profit": "USD",
        "net_income": "USD",
        "operating_cash_flow": "USD",
        "operating_income": "USD",
        "revenue": "USD",
        "stockholders_equity": "USD",
        "total_assets": "USD",
        "total_liabilities": "USD"
      },
      "fundamentals": {
        "capex": 9387000.0,
        "cash": 65919000.0,
        "cost_of_revenue": 425870000.0,
        "eps_diluted": 3.49,
        "free_cash_flow": 70697000.0,
        "gross_profit": 255682000.0,
        "net_income": 52557000.0,
        "operating_cash_flow": 80084000.0,
        "operating_income": 44147000.0,
        "revenue": 681552000.0,
        "stockholders_equity": 304851000.0,
        "total_assets": 544211000.0,
        "total_liabilities": 239360000.0
      },
      "period_end": "2026-01-02",
      "ratio_units": {
        "gross_margin": "ratio",
        "leverage": "ratio",
        "net_margin": "ratio",
        "operating_margin": "ratio",
        "roa_period_end": "ratio",
        "roe_period_end": "ratio"
      },
      "ratios": {
        "gross_margin": 0.3751467239476958,
        "leverage": 0.7851704603232399,
        "net_margin": 0.07711370519050638,
        "operating_margin": 0.06477422118928564,
        "roa_period_end": 0.09657467416130876,
        "roe_period_end": 0.17240225552811045
      }
    },
    {
      "accn": "0001104659-26-020767",
      "filed": "2026-02-27",
      "fiscal_year": 2024,
      "form": "10-K",
      "fundamental_units": {
        "capex": "USD",
        "cash": "USD",
        "cost_of_revenue": "USD",
        "eps_diluted": "USD/shares",
        "free_cash_flow": "USD",
        "gross_profit": "USD",
        "net_income": "USD",
        "operating_cash_flow": "USD",
        "operating_income": "USD",
        "revenue": "USD",
        "stockholders_equity": "USD",
        "total_assets": "USD",
        "total_liabilities": "USD"
      },
      "fundamentals": {
        "capex": 8413000.0,
        "cash": 74158000.0,
        "cost_of_revenue": 363016000.0,
        "eps_diluted": 1.58,
        "free_cash_flow": 63660000.0,
        "gross_profit": 202782000.0,
        "net_income": 22570000.0,
        "operating_cash_flow": 72073000.0,
        "operating_income": 31353000.0,
        "revenue": 565798000.0,
        "stockholders_equity": 234343000.0,
        "total_assets": 464863000.0,
        "total_liabilities": 230520000.0
      },
      "period_end": "2024-12-27",
      "ratio_units": {
        "gross_margin": "ratio",
        "leverage": "ratio",
        "net_margin": "ratio",
        "operating_margin": "ratio",
        "revenue_growth_yoy": "ratio",
        "roa_avg2y": "ratio",
        "roa_period_end": "ratio",
        "roe_avg2y": "ratio",
        "roe_period_end": "ratio"
      },
      "ratios": {
        "gross_margin": 0.3583999943442713,
        "leverage": 0.9836863059703085,
        "net_margin": 0.039890561649210496,
        "operating_margin": 0.05541376957854217,
        "revenue_growth_yoy": 0.10920122722238014,
        "roa_avg2y": 0.05126917909117032,
        "roa_period_end": 0.048551938958359776,
        "roe_avg2y": 0.10396418141450248,
        "roe_period_end": 0.09631181644000461
      }
    },
    {
      "accn": "0001104659-26-020767",
      "filed": "2026-02-27",
      "fiscal_year": 2023,
      "form": "10-K",
      "fundamental_units": {
        "capex": "USD",
        "cash": "USD",
        "cost_of_revenue": "USD",
        "eps_diluted": "USD/shares",
        "free_cash_flow": "USD",
        "gross_profit": "USD",
        "net_income": "USD",
        "operating_cash_flow": "USD",
        "operating_income": "USD",
        "revenue": "USD",
        "stockholders_equity": "USD",
        "total_assets": "USD",
        "total_liabilities": "USD"
      },
      "fundamentals": {
        "capex": 9925000.0,
        "cash": 23397000.0,
        "cost_of_revenue": 330328000.0,
        "eps_diluted": 0.8,
        "free_cash_flow": 29289000.0,
        "gross_profit": 179767000.0,
        "net_income": 10926000.0,
        "operating_cash_flow": 39214000.0,
        "operating_income": 22074000.0,
        "revenue": 510095000.0,
        "stockholders_equity": 199845000.0,
        "total_assets": 415588000.0,
        "total_liabilities": 215743000.0
      },
      "period_end": "2023-12-29",
      "ratio_units": {
        "gross_margin": "ratio",
        "leverage": "ratio",
        "net_margin": "ratio",
        "operating_margin": "ratio",
        "revenue_growth_yoy": "ratio",
        "roa_avg2y": "ratio",
        "roa_period_end": "ratio",
        "roe_avg2y": "ratio",
        "roe_period_end": "ratio"
      },
      "ratios": {
        "gross_margin": 0.3524186671110283,
        "leverage": 1.0795516525307114,
        "net_margin": 0.021419539497544576,
        "operating_margin": 0.04327429204363893,
        "revenue_growth_yoy": 0.18865027100839357,
        "roa_avg2y": 0.026478863682079145,
        "roa_period_end": 0.026290460744776076,
        "roe_avg2y": 0.057302142143507095,
        "roe_period_end": 0.05467237108759289
      }
    },
    {
      "accn": "0001558370-25-002429",
      "filed": "2025-03-07",
      "fiscal_year": 2022,
      "form": "10-K",
      "fundamental_units": {
        "capex": "USD",
        "cash": "USD",
        "cost_of_revenue": "USD",
        "eps_diluted": "USD/shares",
        "free_cash_flow": "USD",
        "gross_profit": "USD",
        "net_income": "USD",
        "operating_cash_flow": "USD",
        "operating_income": "USD",
        "revenue": "USD",
        "stockholders_equity": "USD",
        "total_assets": "USD",
        "total_liabilities": "USD"
      },
      "fundamentals": {
        "capex": 9602000.0,
        "cash": 8806000.0,
        "cost_of_revenue": 285559000.0,
        "eps_diluted": -0.65,
        "free_cash_flow": -169000.0,
        "gross_profit": 143579000.0,
        "net_income": -8448000.0,
        "operating_cash_flow": 9433000.0,
        "operating_income": -7063000.0,
        "revenue": 429138000.0,
        "stockholders_equity": 181502000.0,
        "total_assets": 409674000.0,
        "total_liabilities": 228172000.0
      },
      "period_end": "2022-12-30",
      "ratio_units": {
        "gross_margin": "ratio",
        "leverage": "ratio",
        "net_margin": "ratio",
        "operating_margin": "ratio",
        "revenue_growth_yoy": "ratio",
        "roa_avg2y": "ratio",
        "roa_period_end": "ratio",
        "roe_avg2y": "ratio",
        "roe_period_end": "ratio"
      },
      "ratios": {
        "gross_margin": 0.3345753580433334,
        "leverage": 1.2571321528137431,
        "net_margin": -0.019685975140863777,
        "operating_margin": -0.016458575097055027,
        "revenue_growth_yoy": 0.213093807861373,
        "roa_avg2y": -0.021012416427889206,
        "roa_period_end": -0.020621274476779097,
        "roe_avg2y": -0.046839264477175006,
        "roe_period_end": -0.04654494165353549
      }
    },
    {
      "accn": "0001558370-24-002758",
      "filed": "2024-03-08",
      "fiscal_year": 2021,
      "form": "10-K",
      "fundamental_units": {
        "capex": "USD",
        "cash": "USD",
        "cost_of_revenue": "USD",
        "eps_diluted": "USD/shares",
        "free_cash_flow": "USD",
        "gross_profit": "USD",
        "net_income": "USD",
        "operating_cash_flow": "USD",
        "operating_income": "USD",
        "revenue": "USD",
        "stockholders_equity": "USD",
        "total_assets": "USD",
        "total_liabilities": "USD"
      },
      "fundamentals": {
        "capex": 8500000.0,
        "cash": 11221000.0,
        "cost_of_revenue": 217881000.0,
        "eps_diluted": -0.68,
        "free_cash_flow": 1304000.0,
        "gross_profit": 135874000.0,
        "net_income": -8417000.0,
        "operating_cash_flow": 9804000.0,
        "operating_income": -8691000.0,
        "revenue": 353755000.0,
        "stockholders_equity": 179221000.0,
        "total_assets": 394422000.0,
        "total_liabilities": 215201000.0
      },
      "period_end": "2021-12-31",
      "ratio_units": {
        "gross_margin": "ratio",
        "leverage": "ratio",
        "net_margin": "ratio",
        "operating_margin": "ratio",
        "roa_period_end": "ratio",
        "roe_period_end": "ratio"
      },
      "ratios": {
        "gross_margin": 0.3840906842306116,
        "leverage": 1.2007577237042535,
        "net_margin": -0.023793303274865375,
        "operating_margin": -0.024567850631086484,
        "roa_period_end": -0.021340087520472995,
        "roe_period_end": -0.046964362435205693
      }
    },
    {
      "accn": "0001558370-22-004402",
      "filed": "2022-03-25",
      "fiscal_year": 2019,
      "form": "10-K",
      "fundamental_units": {
        "capex": "USD",
        "cash": "USD",
        "eps_diluted": "USD/shares",
        "free_cash_flow": "USD",
        "operating_cash_flow": "USD",
        "operating_income": "USD",
        "revenue": "USD",
        "stockholders_equity": "USD",
        "total_assets": "USD",
        "total_liabilities": "USD"
      },
      "fundamentals": {
        "capex": 6637000.0,
        "cash": 5452000.0,
        "eps_diluted": 0.41,
        "free_cash_flow": 4984000.0,
        "operating_cash_flow": 11621000.0,
        "operating_income": 9363000.0,
        "revenue": 443099000.0,
        "stockholders_equity": 167278000.0,
        "total_assets": 439913000.0,
        "total_liabilities": 272635000.0
      },
      "period_end": "2019-12-27",
      "ratio_units": {
        "leverage": "ratio",
        "operating_margin": "ratio",
        "revenue_growth_yoy": "ratio"
      },
      "ratios": {
        "leverage": 1.6298317770418107,
        "operating_margin": 0.02113071796596246,
        "revenue_growth_yoy": 0.6275325801096043
      }
    },
    {
      "accn": "0001558370-22-004402",
      "filed": "2022-03-25",
      "fiscal_year": 2018,
      "form": "10-K",
      "fundamental_units": {
        "capex": "USD",
        "cash": "USD",
        "eps_diluted": "USD/shares",
        "free_cash_flow": "USD",
        "operating_cash_flow": "USD",
        "operating_income": "USD",
        "revenue": "USD",
        "stockholders_equity": "USD",
        "total_assets": "USD",
        "total_liabilities": "USD"
      },
      "fundamentals": {
        "capex": 2105000.0,
        "cash": 15259000.0,
        "eps_diluted": 1.03,
        "free_cash_flow": 5463000.0,
        "operating_cash_flow": 7568000.0,
        "operating_income": 12771000.0,
        "revenue": 272252000.0,
        "stockholders_equity": 144289000.0,
        "total_assets": 300911000.0,
        "total_liabilities": 156622000.0
      },
      "period_end": "2018-12-28",
      "ratio_units": {
        "leverage": "ratio",
        "operating_margin": "ratio",
        "revenue_growth_yoy": "ratio"
      },
      "ratios": {
        "leverage": 1.0854742911795079,
        "operating_margin": 0.04690874630856706,
        "revenue_growth_yoy": -0.004024115426263572
      }
    },
    {
      "accn": "0001558370-21-003104",
      "filed": "2021-03-17",
      "fiscal_year": 2017,
      "form": "10-K",
      "fundamental_units": {
        "capex": "USD",
        "cash": "USD",
        "eps_diluted": "USD/shares",
        "free_cash_flow": "USD",
        "operating_cash_flow": "USD",
        "operating_income": "USD",
        "revenue": "USD",
        "stockholders_equity": "USD",
        "total_assets": "USD",
        "total_liabilities": "USD"
      },
      "fundamentals": {
        "capex": 2178000.0,
        "cash": 14424000.0,
        "eps_diluted": 1.32,
        "free_cash_flow": 8891000.0,
        "operating_cash_flow": 11069000.0,
        "operating_income": 13704000.0,
        "revenue": 273352000.0,
        "stockholders_equity": 70652000.0,
        "total_assets": 138172000.0,
        "total_liabilities": 67520000.0
      },
      "period_end": "2017-12-29",
      "ratio_units": {
        "leverage": "ratio",
        "operating_margin": "ratio",
        "revenue_growth_yoy": "ratio"
      },
      "ratios": {
        "leverage": 0.9556700447262639,
        "operating_margin": 0.05013316163774181,
        "revenue_growth_yoy": 0.30827362748335657
      }
    },
    {
      "accn": "0001558370-20-002100",
      "filed": "2020-03-06",
      "fiscal_year": 2016,
      "form": "10-K",
      "fundamental_units": {
        "capex": "USD",
        "cash": "USD",
        "eps_diluted": "USD/shares",
        "free_cash_flow": "USD",
        "operating_cash_flow": "USD",
        "operating_income": "USD",
        "revenue": "USD",
        "stockholders_equity": "USD",
        "total_assets": "USD",
        "total_liabilities": "USD"
      },
      "fundamentals": {
        "capex": 1662000.0,
        "cash": 22668000.0,
        "eps_diluted": 0.97,
        "free_cash_flow": 19938000.0,
        "operating_cash_flow": 21600000.0,
        "operating_income": 11544000.0,
        "revenue": 208941000.0,
        "stockholders_equity": 49918000.0,
        "total_assets": 108347000.0,
        "total_liabilities": 58429000.0
      },
      "period_end": "2016-12-30",
      "ratio_units": {
        "leverage": "ratio",
        "operating_margin": "ratio"
      },
      "ratios": {
        "leverage": 1.1704996193757762,
        "operating_margin": 0.055250046663890766
      }
    },
    {
      "accn": "0001558370-18-001811",
      "filed": "2018-03-09",
      "fiscal_year": 2015,
      "form": "10-K",
      "fundamental_units": {
        "capex": "USD",
        "cash": "USD",
        "eps_diluted": "USD/shares",
        "operating_income": "USD",
        "stockholders_equity": "USD",
        "total_assets": "USD",
        "total_liabilities": "USD"
      },
      "fundamentals": {
        "capex": 492000.0,
        "cash": 18173000.0,
        "eps_diluted": 1.22,
        "operating_income": 8309000.0,
        "stockholders_equity": 30413000.0,
        "total_assets": 49330000.0,
        "total_liabilities": 18917000.0
      },
      "period_end": "2015-01-02",
      "ratio_units": {
        "leverage": "ratio"
      },
      "ratios": {
        "leverage": 0.6220037483970671
      }
    }
  ],
  "latest_filing": {
    "accn": "0001104659-26-020767",
    "filed": "2026-02-27",
    "form": "10-K"
  },
  "note": "Static grepcent export of verified SEC companyfacts-derived values. Monetary values are raw reported units from grepcent's resolved facts; no scaling and no FX conversion. Capex, dividends, and buybacks are reported as positive outflow magnitudes. ROE/ROA include both period-end basis (site-consistent) and average-of-two-years basis where the prior-year denominator exists.",
  "schema_version": "1",
  "sic": "8711",
  "sic_description": "Services-Engineering Services",
  "source_urls": {
    "sec_companyfacts": "https://data.sec.gov/api/xbrl/companyfacts/CIK0001370450.json",
    "sec_submissions": "https://data.sec.gov/submissions/CIK0001370450.json"
  },
  "ticker": "WLDN"
}
