Note 15 - Net Loss Per Share Attributable to Sterling Common Stockholders (Details) - Basic Net Income (Loss) per Share Attributable to Sterling Common Stockholders (USD $)
In Thousands, except Share data, unless otherwise specified

3 Months Ended

12 Months Ended

Dec. 31, 2014

Sep. 30, 2014

Jun. 30, 2014

Mar. 31, 2014

Dec. 31, 2013

Sep. 30, 2013

Jun. 30, 2013

Mar. 31, 2013

Dec. 31, 2014

Dec. 31, 2013

Dec. 31, 2012

Numerator:

Net loss attributable to Sterling common stockholders

$ (7,251)us-gaap_NetIncomeLoss

$ (3,935)us-gaap_NetIncomeLoss

$ 1,200us-gaap_NetIncomeLoss

$ 205us-gaap_NetIncomeLoss

$ (52,135)us-gaap_NetIncomeLoss

$ (189)us-gaap_NetIncomeLoss

$ (17,025)us-gaap_NetIncomeLoss

$ (4,580)us-gaap_NetIncomeLoss

$ (9,781)us-gaap_NetIncomeLoss

$ (73,929)us-gaap_NetIncomeLoss

$ (297)us-gaap_NetIncomeLoss

Revaluation of noncontrolling interest put/call liability reflected in additional paid in capital or retained earnings, net of tax

(7,686)strl_RevaluationOfNoncontrollingInterestObligationsReflectedInRetainedEarningsNetOfTax

(3,992)strl_RevaluationOfNoncontrollingInterestObligationsReflectedInRetainedEarningsNetOfTax

$ (9,781)us-gaap_IncomeLossFromContinuingOperations

$ (81,615)us-gaap_IncomeLossFromContinuingOperations

$ (4,289)us-gaap_IncomeLossFromContinuingOperations

Denominator:

Weighted average common shares outstanding — basic (in Shares)

18,063,000us-gaap_WeightedAverageNumberOfSharesOutstandingBasic

16,635,000us-gaap_WeightedAverageNumberOfSharesOutstandingBasic

16,421,000us-gaap_WeightedAverageNumberOfSharesOutstandingBasic

Weighted average common shares outstanding and assumed conversions— diluted (in Shares)

18,063,466us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted

16,635,179us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted

16,420,886us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted

Basic and diluted net loss per share attributable to Sterling common stockholders (in Dollars per share)

$ (0.54)us-gaap_EarningsPerShareBasicAndDiluted

$ (4.91)us-gaap_EarningsPerShareBasicAndDiluted

$ (0.26)us-gaap_EarningsPerShareBasicAndDiluted

- Details

Name:	strl_DenominatorAbstract
Namespace Prefix:	strl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	strl_NumeratorAbstract
Namespace Prefix:	strl_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The revaluation of noncontrolling interest obligations reflected in retained earnings, net of tax.

+ References

No definition available.

+ Details

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

- Definition

The amount of net income or loss for the period per each share in instances when basic and diluted earnings per share are the same amount and reported as a single line item on the face of the financial statements. Basic earnings per share is the amount of net income or loss for the period per each share of common stock or unit outstanding during the reporting period. Diluted earnings per share includes the amount of net income or loss for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

+ References

No definition available.

+ Details

Name:	us-gaap_EarningsPerShareBasicAndDiluted
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of income (loss) from continuing operations attributable to the parent. Also defined as revenue less expenses and taxes from ongoing operations before extraordinary items but after deduction of those portions of income or loss from continuing operations that are allocable to noncontrolling interests.

+ References

+ Details

Name:	us-gaap_IncomeLossFromContinuingOperations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Other Comprehensive Income

-URI http://asc.fasb.org/extlink&oid=6519514

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Net Income

-URI http://asc.fasb.org/extlink&oid=6518256

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.19)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.18)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 225

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-04.22)

-URI http://asc.fasb.org/extlink&oid=6879464&loc=d3e573970-122913

Reference 8: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 19

-Article 5

Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 20

-Article 9

+ Details

Name:	us-gaap_NetIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Average number of shares or units issued and outstanding that are used in calculating basic and diluted earnings per share (EPS).

+ References

No definition available.

+ Details

Name:	us-gaap_WeightedAverageNumberOfShareOutstandingBasicAndDiluted
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of [basic] shares or units, after adjustment for contingently issuable shares or units and other shares or units not deemed outstanding, determined by relating the portion of time within a reporting period that common shares or units have been outstanding to the total time in that period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 45

-Paragraph 10

-URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1448-109256

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Weighted-Average Number of Common Shares Outstanding

-URI http://asc.fasb.org/extlink&oid=6528421

+ Details

Name:	us-gaap_WeightedAverageNumberOfSharesOutstandingBasic
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration