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Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) (USD $) | 1 Months Ended | 3 Months Ended | 12 Months Ended | 1 Months Ended | 0 Months Ended | 3 Months Ended | 36 Months Ended | 1 Months Ended |  |  |
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Jun. 30, 2014 | Dec. 31, 2013 | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 | Aug. 31, 2011 | Jan. 23, 2014 | Aug. 01, 2011 | Mar. 31, 2014 | Dec. 31, 2012 | Apr. 30, 2013 | Sep. 30, 2013 | Dec. 31, 2009 | Apr. 27, 2012
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Adjustments to Additional Paid in Capital, Other |  |  | $ (116,000)us-gaap_AdjustmentsToAdditionalPaidInCapitalOther |  |  |  |  |  |  |  |  |  |  |
Related Party Transaction, Amounts of Transaction |  |  | 400,000 us-gaap_RelatedPartyTransactionAmountsOfTransaction | 400,000 us-gaap_RelatedPartyTransactionAmountsOfTransaction | 400,000 us-gaap_RelatedPartyTransactionAmountsOfTransaction |  |  |  |  |  |  |  |  |
Liquidation Value Multiplier |  |  |  |  | 4.5 strl_LiquidationValueMultiplier |  |  |  |  |  |  |  |  |
|  |  | 3,200,000 strl_MandatoryRedemptionEarningsDistributed |  |  |  |  |  |  |  |  |  |  |
Obligation For Noncontrolling Owners Interest In Subsidiaries And Joint Ventures |  | 196,000 strl_ObligationForNoncontrollingOwnersInterestInSubsidiariesAndJointVentures |  | 196,000 strl_ObligationForNoncontrollingOwnersInterestInSubsidiariesAndJointVentures |  |  |  |  |  |  |  | 17,800,000 strl_ObligationForNoncontrollingOwnersInterestInSubsidiariesAndJointVentures |  |
Redeemable Noncontrolling Interest, Equity, Fair Value |  |  |  |  |  |  |  |  |  |  |  | 14,100,000 us-gaap_RedeemableNoncontrollingInterestEquityFairValue |  |
Undistributed Earnings of Domestic Subsidiaries |  | 3,989,000 us-gaap_UndistributedEarningsOfDomesticSubsidiaries | 6,079,000 us-gaap_UndistributedEarningsOfDomesticSubsidiaries | 3,989,000 us-gaap_UndistributedEarningsOfDomesticSubsidiaries |  |  |  |  |  |  |  | 3,700,000 us-gaap_UndistributedEarningsOfDomesticSubsidiaries |  |
Increase in Undistributed Earnings |  | 300,000 strl_IncreaseInUndistributedEarnings |  |  |  |  |  |  |  |  |  |  |  |
Sale of Ancillary Company Equity Percentage | 50.00%strl_SaleOfAncillaryCompanyEquityPercentage |  |  |  |  |  |  |  |  |  |  |  |  |
Net Income (Loss) Attributable to Noncontrolling Interest |  |  | 4,556,000 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | 3,903,000 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest | 18,009,000 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest |  |  |  |  |  |  |  |  |
Payments to Noncontrolling Interests |  |  | 1,191,000 us-gaap_PaymentsToMinorityShareholders | 3,565,000 us-gaap_PaymentsToMinorityShareholders | 10,185,000 us-gaap_PaymentsToMinorityShareholders |  |  |  |  |  |  |  |  |
Net Income Attributable To Noncontrolling Interest Included In Liabilities |  |  |  | 2,024,000 strl_NetIncomeAttributableToNoncontrollingInterestIncludedInLiabilities | 16,941,000 strl_NetIncomeAttributableToNoncontrollingInterestIncludedInLiabilities |  |  |  |  |  |  |  |  |
Net Income Attributable To Noncontrolling Interest Included In Equity |  |  | 4,556,000 strl_NetIncomeAttributableToNoncontrollingInterestIncludedInEquity | 1,879,000 strl_NetIncomeAttributableToNoncontrollingInterestIncludedInEquity | 1,068,000 strl_NetIncomeAttributableToNoncontrollingInterestIncludedInEquity |  |  |  |  |  |  |  |  |
Other Operating Income (Expense) [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Undistributed Earnings, Basic |  |  | 2,100,000 us-gaap_UndistributedEarnings / us-gaap_IncomeStatementLocationAxis = us-gaap_OtherOperatingIncomeExpenseMember |  |  |  |  |  |  |  |  |  |  |
RHB [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition Pre-Tax Adjustment |  |  |  |  | 1,300,000 strl_BusinessAcquisitionPreTaxAdjustment / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = strl_RHBMember |  |  |  |  |  |  |  |  |
Upon Death [Member] | CEO of RHB [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Obligation to Purchase Member Interest |  | 20,000,000 strl_ObligationToPurchaseMemberInterest / us-gaap_StatementScenarioAxis = strl_UponDeathMember / us-gaap_TitleOfIndividualAxis = strl_CEOOfRHBMember |  | 20,000,000 strl_ObligationToPurchaseMemberInterest / us-gaap_StatementScenarioAxis = strl_UponDeathMember / us-gaap_TitleOfIndividualAxis = strl_CEOOfRHBMember |  |  |  |  |  |  |  |  |  |
Cash Surrender Value of Life Insurance |  | 20,000,000 us-gaap_CashSurrenderValueOfLifeInsurance / us-gaap_StatementScenarioAxis = strl_UponDeathMember / us-gaap_TitleOfIndividualAxis = strl_CEOOfRHBMember |  | 20,000,000 us-gaap_CashSurrenderValueOfLifeInsurance / us-gaap_StatementScenarioAxis = strl_UponDeathMember / us-gaap_TitleOfIndividualAxis = strl_CEOOfRHBMember |  |  |  |  |  |  |  |  |  |
Upon Permanent Disability [Member] | CEO of RHB [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Obligation to Purchase Member Interest |  | 18,000,000 strl_ObligationToPurchaseMemberInterest / us-gaap_StatementScenarioAxis = strl_UponPermanentDisabilityMember / us-gaap_TitleOfIndividualAxis = strl_CEOOfRHBMember |  | 18,000,000 strl_ObligationToPurchaseMemberInterest / us-gaap_StatementScenarioAxis = strl_UponPermanentDisabilityMember / us-gaap_TitleOfIndividualAxis = strl_CEOOfRHBMember |  |  |  |  |  |  |  |  |  |
Years 2011 to 2015 [Member] | JBC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition Earn-Out Calculated Floor |  |  |  |  |  | 2,000,000 strl_BusinessAcquisitionEarnOutCalculatedFloor / us-gaap_BusinessAcquisitionAxis = strl_JBCMember / us-gaap_StatementScenarioAxis = strl_Years2011To2015Member |  |  |  |  |  |  |  |
Seven Months Ended 2016 [Member] | JBC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition Earn-Out Calculated Floor |  |  |  |  |  | 1,200,000 strl_BusinessAcquisitionEarnOutCalculatedFloor / us-gaap_BusinessAcquisitionAxis = strl_JBCMember / us-gaap_StatementScenarioAxis = strl_SevenMonthsEndedTwoThousandSixteenMember |  |  |  |  |  |  |  |
Original Earn-out Liability [Member] | JBC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition Undiscounted Earn-Out Liability |  |  |  |  |  |  | 5,000,000 strl_BusinessAcquisitionUndiscountedEarnOutLiability / us-gaap_BusinessAcquisitionAxis = strl_JBCMember / us-gaap_StatementScenarioAxis = strl_OriginalEarnoutLiabilityMember |  |  |  |  |  |  |
If certain EBITDA thresholds are met [Member] | JBC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition Undiscounted Earn-Out Liability |  |  |  |  |  |  | 10,000,000 strl_BusinessAcquisitionUndiscountedEarnOutLiability / us-gaap_BusinessAcquisitionAxis = strl_JBCMember / us-gaap_StatementScenarioAxis = strl_IfCertainEBITDAThresholdsAreMetMember |  |  |  |  |  |  |
For 2014 and 2015 [Member] | JBC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition Earn-Out Calculated Floor |  |  |  |  |  |  | 1,500,000 strl_BusinessAcquisitionEarnOutCalculatedFloor / us-gaap_BusinessAcquisitionAxis = strl_JBCMember / us-gaap_StatementScenarioAxis = strl_ForTwoThousandFourteenAndTwoThousandFifteenMember |  |  |  |  |  |  |
For 2016 and 2017 [Member] | JBC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition Earn-Out Calculated Floor |  |  |  |  |  |  | 2,000,000 strl_BusinessAcquisitionEarnOutCalculatedFloor / us-gaap_BusinessAcquisitionAxis = strl_JBCMember / us-gaap_StatementScenarioAxis = strl_ForTwoThousandSixteenAndTwoThousandSeventeenMember |  |  |  |  |  |  |
For the Years 2015 Through 2017 [Member] | JBC [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Forcasted EBITDA Percentage |  |  |  |  |  |  | 0.00%strl_ForcastedEBITDAPercentage / us-gaap_BusinessAcquisitionAxis = strl_JBCMember / us-gaap_RangeAxis = us-gaap_MinimumMember / us-gaap_StatementScenarioAxis = strl_ForTheYears2015Through2017Member |  |  |  |  |  |  |
For the Years 2015 Through 2017 [Member] | JBC [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Forcasted EBITDA Percentage |  |  |  |  |  |  | 22.40%strl_ForcastedEBITDAPercentage / us-gaap_BusinessAcquisitionAxis = strl_JBCMember / us-gaap_RangeAxis = us-gaap_MaximumMember / us-gaap_StatementScenarioAxis = strl_ForTheYears2015Through2017Member |  |  |  |  |  |  |
RHBP [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net |  |  |  |  | 9,800,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet / us-gaap_BusinessAcquisitionAxis = strl_RHBPMember |  |  |  |  | 9,800,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet / us-gaap_BusinessAcquisitionAxis = strl_RHBPMember |  |  |  |
Adjustments to Additional Paid in Capital, Other |  |  |  |  | 233,000 us-gaap_AdjustmentsToAdditionalPaidInCapitalOther / us-gaap_BusinessAcquisitionAxis = strl_RHBPMember |  |  |  |  |  |  |  |  |
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Liabilities Noncurrent |  |  |  |  | 360,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent / us-gaap_BusinessAcquisitionAxis = strl_RHBPMember |  |  |  |  | 360,000 us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent / us-gaap_BusinessAcquisitionAxis = strl_RHBPMember |  |  |  |
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual |  |  |  |  | 152,000 us-gaap_BusinessCombinationProFormaInformationEarningsOrLossOfAcquireeSinceAcquisitionDateActual / us-gaap_BusinessAcquisitionAxis = strl_RHBPMember |  |  |  |  |  |  |  |  |
Net Income (Loss) Attributable to Noncontrolling Interest |  |  |  |  | 1,900,000 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / us-gaap_BusinessAcquisitionAxis = strl_RHBPMember |  |  |  |  |  |  |  |  |
Contracts Assumed [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual |  |  |  |  | 26,100,000 us-gaap_BusinessCombinationProFormaInformationRevenueOfAcquireeSinceAcquisitionDateActual / us-gaap_BusinessAcquisitionAxis = strl_ContractsAssumedMember |  |  |  |  |  |  |  |  |
JBC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition Additional Price Payments Term |  |  |  |  |  | 5 years |  |  |  |  |  |  |  |
Business Acquisition Additional Price Payments |  |  |  |  |  | 5,000,000 strl_BusinessAcquisitionAdditionalPricePayments / us-gaap_BusinessAcquisitionAxis = strl_JBCMember |  |  |  |  |  |  |  |
Business Acquisition Earn-Out Percentage |  |  |  |  |  | 50.00%strl_BusinessAcquisitionEarnOutPercentage / us-gaap_BusinessAcquisitionAxis = strl_JBCMember |  |  |  |  |  |  |  |
Business Acquisition Discounted Earn-Out Liability |  | 600,000 strl_BusinessAcquisitionDiscountedEarnOutLiability / us-gaap_BusinessAcquisitionAxis = strl_JBCMember |  | 600,000 strl_BusinessAcquisitionDiscountedEarnOutLiability / us-gaap_BusinessAcquisitionAxis = strl_JBCMember |  |  |  |  |  |  |  |  |  |
Business Acquisition Undiscounted Earn-Out Liability |  | 1,400,000 strl_BusinessAcquisitionUndiscountedEarnOutLiability / us-gaap_BusinessAcquisitionAxis = strl_JBCMember | 300,000 strl_BusinessAcquisitionUndiscountedEarnOutLiability / us-gaap_BusinessAcquisitionAxis = strl_JBCMember | 1,400,000 strl_BusinessAcquisitionUndiscountedEarnOutLiability / us-gaap_BusinessAcquisitionAxis = strl_JBCMember |  |  |  |  |  |  |  |  |  |
Payment for Amendment to the Earn-out Liability |  |  |  |  |  |  |  |  | 800,000 strl_PaymentforAmendmenttotheEarnoutLiability / us-gaap_BusinessAcquisitionAxis = strl_JBCMember |  |  |  |  |
Business Acquisition, Cost of Acquired Entity, Discounted Present Value of Additional Purchase Price |  |  | 300,000 strl_BusinessAcquisitionCostOfAcquiredEntityDiscountedPresentValueOfAdditionalPurchasePrice / us-gaap_BusinessAcquisitionAxis = strl_JBCMember |  |  |  |  | 2,400,000 strl_BusinessAcquisitionCostOfAcquiredEntityDiscountedPresentValueOfAdditionalPurchasePrice / us-gaap_BusinessAcquisitionAxis = strl_JBCMember |  |  |  |  |  |
Business Acquisition Undiscounted Earn-Out Liability Increase |  |  | 9,000,000 strl_BusinessAcquisitionUndiscountedEarnOutLiabilityIncrease / us-gaap_BusinessAcquisitionAxis = strl_JBCMember |  |  |  |  |  |  |  |  |  |  |
EBITDA Earn-Out Increase Floor |  |  | 18,000,000 strl_EBITDAEarnOutIncreaseFloor / us-gaap_BusinessAcquisitionAxis = strl_JBCMember |  |  |  |  |  |  |  |  |  |  |
Interest Expense |  |  | 300,000 us-gaap_InterestExpense / us-gaap_BusinessAcquisitionAxis = strl_JBCMember | 100,000 us-gaap_InterestExpense / us-gaap_BusinessAcquisitionAxis = strl_JBCMember | 100,000 us-gaap_InterestExpense / us-gaap_BusinessAcquisitionAxis = strl_JBCMember |  |  |  |  |  |  |  |  |
RLW [Member] | Minimum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition Purchase Price Multiplier |  |  |  |  |  |  |  |  |  | 4 strl_BusinessAcquisitionPurchasePriceMultiplier / us-gaap_BusinessAcquisitionAxis = strl_RLWMember / us-gaap_RangeAxis = us-gaap_MinimumMember |  |  |  |
RLW [Member] | Maximum [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition Purchase Price Multiplier |  |  |  |  |  |  |  |  |  | 4.5 strl_BusinessAcquisitionPurchasePriceMultiplier / us-gaap_BusinessAcquisitionAxis = strl_RLWMember / us-gaap_RangeAxis = us-gaap_MaximumMember |  |  |  |
RLW [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Acquisition Additional Price Payments |  |  |  |  | 23,100,000 strl_BusinessAcquisitionAdditionalPricePayments / us-gaap_BusinessAcquisitionAxis = strl_RLWMember |  |  |  |  |  | 509,000 strl_BusinessAcquisitionAdditionalPricePayments / us-gaap_BusinessAcquisitionAxis = strl_RLWMember |  |  |
Business Acquisition Remaining Percentage Of Voting Interests |  |  |  | 20.00%strl_BusinessAcquisitionRemainingPercentageOfVotingInterests / us-gaap_BusinessAcquisitionAxis = strl_RLWMember |  |  |  |  |  |  |  |  |  |
Business Acquisition Purchase Price Percentage |  |  |  |  |  |  |  |  |  | 20.00%strl_BusinessAcquisitionPurchasePricePercentage / us-gaap_BusinessAcquisitionAxis = strl_RLWMember |  |  |  |
Derivative, Basis Spread on Variable Rate |  |  |  |  |  |  |  |  |  |  |  |  | 2.00%us-gaap_DerivativeBasisSpreadOnVariableRate / us-gaap_BusinessAcquisitionAxis = strl_RLWMember |
Accretion Expense |  |  |  |  | 1,000,000 us-gaap_AccretionExpense / us-gaap_BusinessAcquisitionAxis = strl_RLWMember |  |  |  |  |  |  |  |  |
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners |  |  |  |  | 20.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners / us-gaap_BusinessAcquisitionAxis = strl_RLWMember |  |  |  |  | 20.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners / us-gaap_BusinessAcquisitionAxis = strl_RLWMember |  |  |  |
Business Acquisition, Payments of Undistributed Earnings |  |  |  |  |  |  |  |  |  |  | 2,300,000 strl_BusinessAcquisitionPaymentsOfUndistributedEarnings / us-gaap_BusinessAcquisitionAxis = strl_RLWMember |  |  |
Income (Loss) from Continuing Operations Attributable to Noncontrolling Interest |  |  |  |  | 6,700,000 us-gaap_IncomeLossFromContinuingOperationsAttributableToNoncontrollingEntity / us-gaap_BusinessAcquisitionAxis = strl_RLWMember |  |  |  |  |  |  |  |  |
Increase (Decrease) in Income Taxes |  |  |  |  | 2,400,000 us-gaap_IncreaseDecreaseInIncomeTaxes / us-gaap_BusinessAcquisitionAxis = strl_RLWMember |  |  |  |  |  |  |  |  |
Net Income (Loss) Attributable to Noncontrolling Interest |  |  |  |  | 15,000,000 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / us-gaap_BusinessAcquisitionAxis = strl_RLWMember |  |  |  |  |  |  |  |  |
Myers [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Income (Loss) Attributable to Noncontrolling Interest |  |  |  |  | 1,100,000 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest / us-gaap_BusinessAcquisitionAxis = strl_MyersMember |  |  |  |  |  |  |  |  |
CEO of RHB [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Adjustment to Member's Interest |  | 5,900,000 strl_AdjustmentToMembersInterest / us-gaap_TitleOfIndividualAxis = strl_CEOOfRHBMember |  |  |  |  |  |  |  |  |  |  |  |
Current obligations for noncontrolling owners [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Income Attributable To Noncontrolling Interest Included In Liabilities |  |  |  | 100,000 strl_NetIncomeAttributableToNoncontrollingInterestIncludedInLiabilities / us-gaap_BalanceSheetLocationAxis = strl_CurrentObligationsForNoncontrollingOwnersMember |  |  |  |  |  |  |  |  |  |
Member’s interest subject to mandatory redemption [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net Income Attributable To Noncontrolling Interest Included In Liabilities |  |  |  | 2,100,000 strl_NetIncomeAttributableToNoncontrollingInterestIncludedInLiabilities / us-gaap_BalanceSheetLocationAxis = strl_MembersInterestSubjectToMandatoryRedemptionMember |  |  |  |  |  |  |  |  |  |
RHB [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Noncontrolling Interest, Ownership Percentage by Parent |  |  |  |  |  |  |  |  |  |  |  |  |  | 50.00%us-gaap_MinorityInterestOwnershipPercentageByParent / dei_LegalEntityAxis = strl_RHBMember
Related Party Transaction, Amounts of Transaction |  |  |  |  | 5,000,000 us-gaap_RelatedPartyTransactionAmountsOfTransaction / dei_LegalEntityAxis = strl_RHBMember |  |  |  |  |  |  |  |  |
Noncontrolling Interests Offer To Buy Percentage |  |  |  |  | 50.00%strl_NoncontrollingInterestsOfferToBuyPercentage / dei_LegalEntityAxis = strl_RHBMember |  |  |  |  |  |  |  |  |
Noncontrolling Interests Offer To Sell Percentage |  |  |  |  | 50.00%strl_NoncontrollingInterestsOfferToSellPercentage / dei_LegalEntityAxis = strl_RHBMember |  |  |  |  |  |  |  |  |
Revaluation Pre-Tax Charge |  |  |  | 1,900,000 strl_RevaluationPreTaxCharge / dei_LegalEntityAxis = strl_RHBMember | 2,500,000 strl_RevaluationPreTaxCharge / dei_LegalEntityAxis = strl_RHBMember |  |  |  |  |  |  |  |  |
RLW [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Increase (Decrease) in Put/Call Liability |  |  |  |  | 3,800,000 strl_IncreaseDecreaseInPut_CallLiability / dei_LegalEntityAxis = strl_RLWMember |  |  |  |  |  |  |  |  |
SWR, Inc. [Member[ |  |  |  |  |  |  |  |  |  |  |  |  |  |
Note 2 - Acquisitions and Subsidiaries and Joint Ventures with Noncontrolling Owners' Interests (Details) [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |
Number of Assumed Construction Contracts |  |  |  |  | 6 strl_NumberOfAssumedConstructionContracts / us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis = strl_SWRIncMember |  |  |  |  |  |  |  |  |
Deferred Revenue |  |  |  |  | $ 25,000,000 us-gaap_DeferredRevenue / us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis = strl_SWRIncMember |  |  |  |  | 25,000,000 us-gaap_DeferredRevenue / us-gaap_AccountsNotesLoansAndFinancingReceivablesByLegalEntityOfCounterpartyTypeAxis = strl_SWRIncMember |  |  |  |

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