3.26.1 html 167 266 1 true 56 0 false 5 false false R1.htm 75000 - Document - Document And Entity Information Sheet http://www.icf.com/20260331/taxonomy/role/Role_DocumentDocumentAndEntityInformation Document And Entity Information Cover 1 false false R2.htm 75010 - Statement - CONSOLIDATED BALANCE SHEETS (UNAUDITED) Sheet http://www.icf.com/20260331/taxonomy/role/Role_StatementCONSOLIDATEDBALANCESHEETSUNAUDITED CONSOLIDATED BALANCE SHEETS (UNAUDITED) Statements 2 false false R3.htm 75020 - Statement - CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) Sheet http://www.icf.com/20260331/taxonomy/role/Role_StatementCONSOLIDATEDBALANCESHEETSUNAUDITEDParenthetical CONSOLIDATED BALANCE SHEETS (UNAUDITED) (Parenthetical) Statements 3 false false R4.htm 75030 - Statement - CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) Sheet http://www.icf.com/20260331/taxonomy/role/Role_StatementCONSOLIDATEDSTATEMENTSOFCOMPREHENSIVEINCOMEUNAUDITED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) Statements 4 false false R5.htm 75040 - Statement - CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (UNAUDITED) Sheet http://www.icf.com/20260331/taxonomy/role/StatementConsolidatedStatementsOfStockholdersEquityUnaudited CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (UNAUDITED) Statements 5 false false R6.htm 75050 - Statement - CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) Sheet http://www.icf.com/20260331/taxonomy/role/Role_StatementCONSOLIDATEDSTATEMENTSOFCASHFLOWSUNAUDITED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) Statements 6 false false R7.htm 995410 - Disclosure - Pay vs Performance Disclosure Sheet http://xbrl.sec.gov/ecd/role/PvpDisclosure Pay vs Performance Disclosure Notes 7 false false R8.htm 995445 - Disclosure - Insider Trading Arrangements Sheet http://xbrl.sec.gov/ecd/role/InsiderTradingArrangements Insider Trading Arrangements Notes 8 false false R9.htm 995455 - Disclosure - Basis of Presentation Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureBasisOfPresentation1 Basis of Presentation Notes 9 false false R10.htm 995465 - Disclosure - Restricted Cash Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureRestrictedCash Restricted Cash Notes 10 false false R11.htm 995475 - Disclosure - Accounts Receivable, Net Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureAccountsReceivableNet Accounts Receivable, Net Notes 11 false false R12.htm 995495 - Disclosure - Leases Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureLeases Leases Notes 12 false false R13.htm 995515 - Disclosure - Long-term Debt Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureLongtermDebt1 Long-term Debt Notes 13 false false R14.htm 995525 - Disclosure - Revenue Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureRevenue2 Revenue Notes 14 false false R15.htm 995535 - Disclosure - Derivative Instruments and Hedging Activities Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureDerivativeInstrumentsAndHedgingActivities1 Derivative Instruments and Hedging Activities Notes 15 false false R16.htm 995545 - Disclosure - Income Taxes Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureIncomeTaxes Income Taxes Notes 16 false false R17.htm 995565 - Disclosure - Stockholders' Equity Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureStockholdersEquity Stockholders' Equity Notes 17 false false R18.htm 995575 - Disclosure - Stock-based Compensation Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureStockbasedCompensation Stock-based Compensation Notes 18 false false R19.htm 995595 - Disclosure - Earnings Per Share Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureEarningsPerShare Earnings Per Share Notes 19 false false R20.htm 995615 - Disclosure - Fair Value Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureFairValue Fair Value Notes 20 false false R21.htm 995625 - Disclosure - Commitments and Contingencies Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureCommitmentsAndContingencies Commitments and Contingencies Notes 21 false false R22.htm 995635 - Disclosure - Segment Information Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureSegmentInformation Segment Information Notes 22 false false R23.htm 995645 - Disclosure - Subsequent Event Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureSubsequentEvent2 Subsequent Event Notes 23 false false R24.htm 995655 - Disclosure - Basis of Presentation (Policies) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureBasisOfPresentationPolicies Basis of Presentation (Policies) Policies 24 false false R25.htm 995665 - Disclosure - Restricted Cash (Tables) Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureRestrictedCashTables Restricted Cash (Tables) Tables http://www.icf.com/20260331/taxonomy/role/Role_DisclosureRestrictedCash 25 false false R26.htm 995675 - Disclosure - Accounts Receivable, Net (Tables) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureAccountsReceivableNetTables Accounts Receivable, Net (Tables) Tables http://www.icf.com/20260331/taxonomy/role/DisclosureAccountsReceivableNet 26 false false R27.htm 995695 - Disclosure - Leases (Tables) Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureLeasesTables Leases (Tables) Tables http://www.icf.com/20260331/taxonomy/role/Role_DisclosureLeases 27 false false R28.htm 995715 - Disclosure - Long-term Debt (Tables) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureLongtermDebtTables Long-term Debt (Tables) Tables http://www.icf.com/20260331/taxonomy/role/DisclosureLongtermDebt1 28 false false R29.htm 995725 - Disclosure - Revenue (Tables) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureRevenueTables Revenue (Tables) Tables http://www.icf.com/20260331/taxonomy/role/DisclosureRevenue2 29 false false R30.htm 995735 - Disclosure - Income Taxes (Tables) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureIncomeTaxesTables Income Taxes (Tables) Tables http://www.icf.com/20260331/taxonomy/role/Role_DisclosureIncomeTaxes 30 false false R31.htm 995745 - Disclosure - Stockholders' Equity (Tables) Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureStockholdersEquityTables Stockholders' Equity (Tables) Tables http://www.icf.com/20260331/taxonomy/role/Role_DisclosureStockholdersEquity 31 false false R32.htm 995755 - Disclosure - Stock-based Compensation (Tables) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureStockbasedCompensationTables Stock-based Compensation (Tables) Tables http://www.icf.com/20260331/taxonomy/role/DisclosureStockbasedCompensation 32 false false R33.htm 995775 - Disclosure - Earnings Per Share (Tables) Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureEarningsPerShareTables Earnings Per Share (Tables) Tables http://www.icf.com/20260331/taxonomy/role/Role_DisclosureEarningsPerShare 33 false false R34.htm 995785 - Disclosure - Fair Value (Tables) Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureFairValueTables Fair Value (Tables) Tables http://www.icf.com/20260331/taxonomy/role/Role_DisclosureFairValue 34 false false R35.htm 995795 - Disclosure - Segment Information (Tables) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureSegmentInformationTables Segment Information (Tables) Tables http://www.icf.com/20260331/taxonomy/role/DisclosureSegmentInformation 35 false false R36.htm 995805 - Disclosure - Basis of Presentation - Additional Information (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureBasisOfPresentationAdditionalInformationDetails Basis of Presentation - Additional Information (Details) Details 36 false false R37.htm 995815 - Disclosure - Restricted Cash - Reconciliation of Cash and Cash Equivalents, and Restricted Cash to the Total of Cash, Cash Equivalents, and Restricted Cash (Details) Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureRestrictedCashReconciliationOfCashAndCashEquivalentsAndRestrictedCashToTotalOfCashCashEquivalentsAndRestrictedCashDetails Restricted Cash - Reconciliation of Cash and Cash Equivalents, and Restricted Cash to the Total of Cash, Cash Equivalents, and Restricted Cash (Details) Details 37 false false R38.htm 995825 - Disclosure - Restricted Cash - Reconciliation of Cash and Cash Equivalents, and Restricted Cash to the Total of Cash, Cash Equivalents, and Restricted Cash (Parenthetical) (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureRestrictedCashReconciliationOfCashAndCashEquivalentsAndRestrictedCashToTheTotalOfCashCashEquivalentsAndRestrictedCashParenthet Restricted Cash - Reconciliation of Cash and Cash Equivalents, and Restricted Cash to the Total of Cash, Cash Equivalents, and Restricted Cash (Parenthetical) (Details) Details 38 false false R39.htm 995835 - Disclosure - Accounts Receivable, Net - Summary of Accounts Receivable, Net (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureAccountsReceivableNetSummaryOfAccountsReceivableNetDetails Accounts Receivable, Net - Summary of Accounts Receivable, Net (Details) Details 39 false false R40.htm 995845 - Disclosure - Accounts Receivable, Net - Summary of Accounts Receivable, Net (Parenthetical) (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureAccountsReceivableNetSummaryOfAccountsReceivableNetParentheticalDetails Accounts Receivable, Net - Summary of Accounts Receivable, Net (Parenthetical) (Details) Details 40 false false R41.htm 995855 - Disclosure - Accounts Receivable, Net - Summary of Reconciliation of Billed Accounts Receivable Sold to MUFG (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureAccountsReceivableNetSummaryOfReconciliationOfBilledAccountsReceivableSoldToMufgDetails Accounts Receivable, Net - Summary of Reconciliation of Billed Accounts Receivable Sold to MUFG (Details) Details 41 false false R42.htm 995865 - Disclosure - Accounts Receivable, Net - Summary of Reconciliation of Billed Accounts Receivable Sold to MUFG (Parenthetical) (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureAccountsReceivableNetSummaryOfReconciliationOfBilledAccountsReceivableSoldToMufgParentheticalDetails Accounts Receivable, Net - Summary of Reconciliation of Billed Accounts Receivable Sold to MUFG (Parenthetical) (Details) Details 42 false false R43.htm 995875 - Disclosure - Accounts Receivable, Net - Summary of Reconciliation of Cash Collections from Customers of Billed Accounts Receivable Previously Sold to MUFG (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureAccountsReceivableNetSummaryOfReconciliationOfCashCollectionsFromCustomersOfBilledAccountsReceivablePreviouslySoldToMufgDetails Accounts Receivable, Net - Summary of Reconciliation of Cash Collections from Customers of Billed Accounts Receivable Previously Sold to MUFG (Details) Details 43 false false R44.htm 995885 - Disclosure - Accounts Receivable, Net - Summary of Reconciliation of Cash Collections from Customers of Billed Accounts Receivable Previously Sold to MUFG (Parenthetical) (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureAccountsReceivableNetSummaryOfReconciliationOfCashCollectionsFromCustomersOfBilledAccountsReceivablePreviouslySoldToMufgParenthe Accounts Receivable, Net - Summary of Reconciliation of Cash Collections from Customers of Billed Accounts Receivable Previously Sold to MUFG (Parenthetical) (Details) Details 44 false false R45.htm 995895 - Disclosure - Accounts Receivable, Net - Additional Information (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureAccountsReceivableNetAdditionalInformationDetails Accounts Receivable, Net - Additional Information (Details) Details 45 false false R46.htm 995915 - Disclosure - Leases - Additional Information (Details) Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureLeasesAdditionalInformationDetails Leases - Additional Information (Details) Details 46 false false R47.htm 995925 - Disclosure - Leases - Summary of Future Minimum Lease Payments Under Non-Cancellable Operating and Finance Leases (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureLeasesSummaryOfFutureMinimumLeasePaymentsUnderNoncancellableOperatingAndFinanceLeasesDetails Leases - Summary of Future Minimum Lease Payments Under Non-Cancellable Operating and Finance Leases (Details) Details 47 false false R48.htm 995965 - Disclosure - Long-term Debt - Schedule of Debt (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureLongtermDebtScheduleOfDebtDetails Long-term Debt - Schedule of Debt (Details) Details 48 false false R49.htm 995985 - Disclosure - Long-term Debt - Additional Information (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureLongtermDebtAdditionalInformationDetails Long-term Debt - Additional Information (Details) Details 49 false false R50.htm 995995 - Disclosure - Long-term Debt - Schedule of Future Scheduled Repayments of Term Loan Principal (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureLongtermDebtScheduleOfFutureScheduledRepaymentsOfTermLoanPrincipalDetails Long-term Debt - Schedule of Future Scheduled Repayments of Term Loan Principal (Details) Details 50 false false R51.htm 996005 - Disclosure - Revenue - Disaggregation of Revenue (Detail) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureRevenueDisaggregationOfRevenueDetail Revenue - Disaggregation of Revenue (Detail) Details 51 false false R52.htm 996015 - Disclosure - Revenue - Schedule of Contract Assets and Liabilities and Changes in Contract Balances (Detail) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureRevenueScheduleOfContractAssetsAndLiabilitiesAndChangesInContractBalancesDetail Revenue - Schedule of Contract Assets and Liabilities and Changes in Contract Balances (Detail) Details 52 false false R53.htm 996045 - Disclosure - Revenue - Additional Information (Detail) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureRevenueAdditionalInformationDetail Revenue - Additional Information (Detail) Details 53 false false R54.htm 996055 - Disclosure - Revenue - Additional Information (Detail 1) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureRevenueAdditionalInformationDetail1 Revenue - Additional Information (Detail 1) Details 54 false false R55.htm 996065 - Disclosure - Derivative Instruments and Hedging Activities - Additional Information (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureDerivativeInstrumentsAndHedgingActivitiesAdditionalInformationDetails Derivative Instruments and Hedging Activities - Additional Information (Details) Details 55 false false R56.htm 996085 - Disclosure - Income Taxes - Additional Information (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureIncomeTaxesAdditionalInformationDetails Income Taxes - Additional Information (Details) Details 56 false false R57.htm 996095 - Disclosure - Stockholders' Equity - Components of Accumulated Other Comprehensive Loss (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureStockholdersEquityComponentsOfAccumulatedOtherComprehensiveLossDetails Stockholders' Equity - Components of Accumulated Other Comprehensive Loss (Details) Details 57 false false R58.htm 996105 - Disclosure - Stockholders' Equity - Components of Accumulated Other Comprehensive Loss (Parenthetical) (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureStockholdersEquityComponentsOfAccumulatedOtherComprehensiveLossParentheticalDetails Stockholders' Equity - Components of Accumulated Other Comprehensive Loss (Parenthetical) (Details) Details 58 false false R59.htm 996115 - Disclosure - Stockholders' Equity - Additional Information (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureStockholdersEquityAdditionalInformationDetails Stockholders' Equity - Additional Information (Details) Details 59 false false R60.htm 996125 - Disclosure - Stockholders' Equity - Summary of Repurchase of Shares (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureStockholdersEquitySummaryOfRepurchaseOfSharesDetails Stockholders' Equity - Summary of Repurchase of Shares (Details) Details 60 false false R61.htm 996135 - Disclosure - Stock-based Compensation - Additional Information (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureStockbasedCompensationAdditionalInformationDetails Stock-based Compensation - Additional Information (Details) Details 61 false false R62.htm 996145 - Disclosure - Stock-based Compensation - Schedule Of Awards Granted (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureStockbasedCompensationScheduleOfAwardsGrantedDetails Stock-based Compensation - Schedule Of Awards Granted (Details) Details 62 false false R63.htm 996185 - Disclosure - Earnings Per Share - Schedule of Dilutive Effect of Stock Options RSUs and PSAs (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureEarningsPerShareScheduleOfDilutiveEffectOfStockOptionsRsusAndPsasDetails Earnings Per Share - Schedule of Dilutive Effect of Stock Options RSUs and PSAs (Details) Details 63 false false R64.htm 996195 - Disclosure - Earnings Per Share - Additional Information (Details) Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureEarningsPerShareAdditionalInformationDetails Earnings Per Share - Additional Information (Details) Details 64 false false R65.htm 996205 - Disclosure - Fair Value - Schedule of Financial Instruments Measured at Fair Value on Recurring Basis (Details) Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureFairValueScheduleOfFinancialInstrumentsMeasuredAtFairValueOnRecurringBasisDetails Fair Value - Schedule of Financial Instruments Measured at Fair Value on Recurring Basis (Details) Details 65 false false R66.htm 996215 - Disclosure - Commitments and Contingencies - Additional Information (Details) Sheet http://www.icf.com/20260331/taxonomy/role/Role_DisclosureCommitmentsAndContingenciesAdditionalInformationDetails Commitments and Contingencies - Additional Information (Details) Details 66 false false R67.htm 996225 - Disclosure - Segment Information - Additional Information (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureSegmentInformationAdditionalInformationDetails Segment Information - Additional Information (Details) Details 67 false false R68.htm 996235 - Disclosure - Segment Information - Schedule of Segment Revenue, Significant Segment Expenses, and Segment Profit (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureSegmentInformationScheduleOfSegmentRevenueSignificantSegmentExpensesAndSegmentProfitDetails Segment Information - Schedule of Segment Revenue, Significant Segment Expenses, and Segment Profit (Details) Details 68 false false R69.htm 996255 - Disclosure - Subsequent Event - Additional Information (Details) Sheet http://www.icf.com/20260331/taxonomy/role/DisclosureSubsequentEventAdditionalInformationDetails Subsequent Event - Additional Information (Details) Details 69 false false All Reports Book All Reports icfi-20260331.htm icfi-20260331.xsd http://fasb.org/srt/2025 http://fasb.org/us-gaap/2025 http://xbrl.sec.gov/dei/2025 http://xbrl.sec.gov/ecd/2025 false false