Amount of unpaid project contract price that the Company is entitled to.

No definition available.

Name:	strl_ContractsReceivableUnpaidProjectContractPrice
Namespace Prefix:	strl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Represents net estimated gross profit (loss) before tax.

+ References

No definition available.

+ Details

Name:	strl_EstimatedConstructionGrossProfitLossBeforeTax
Namespace Prefix:	strl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Represents the length of time the Company's contracts generally take to complete.

+ References

No definition available.

+ Details

Name:	strl_RevenueRecognitionPercentageOfCompletionRange
Namespace Prefix:	strl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the warranty term.

+ References

No definition available.

+ Details

Name:	strl_WarrantyTerm
Namespace Prefix:	strl_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of billed or unbilled claims or other similar items subject to uncertainty concerning their determination or ultimate realization under long-term contracts.

+ References

+ Details

Name:	us-gaap_ContractsReceivableClaimsAndUncertainAmounts
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The amount of costs incurred on unapproved change orders when it is probable that the cost will be recovered through a change in the contract price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3)(c)(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 910
-SubTopic 310
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=68065756&loc=d3e49324-109356

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 910
-SubTopic 340
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=68053980&loc=d3e50000-109363

+ Details

Name:	us-gaap_UnapprovedChangeOrdersAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

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Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_OperatingIncomeLossMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
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Period Type:

Summary of Business and Significant Accounting Policies - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Costs and estimated earnings in excess of billings
Business Acquisition [Line Items]
Unapproved change orders, amount	$ 5.0		$ 5.0
Contracts receivable, claims and uncertain amounts	6.0		5.0
Contracts receivable, unpaid project contract price	0.0		$ 0.0
Operating income (Loss)
Business Acquisition [Line Items]
Estimated construction gain (loss) before tax	$ 1.3	$ 0.8
Minimum
Business Acquisition [Line Items]
Revenue recognition, contract term	12 months
Warranty term	1 year
Maximum
Business Acquisition [Line Items]
Revenue recognition, contract term	36 months
Warranty term	2 years