Organization, Business and Significant Accounting Policies (Details Textual) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended										12 Months Ended
	Dec. 31, 2017		Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016		Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jan. 02, 2017
Organization Consolidation and Presentation of Financial Statements [Line Items]
Operating Income (Loss)											$ 29,558	$ 38,754	$ 44,841
Net Income (Loss) Attributable to Parent	$ 13,579	[1]	$ 5,145	$ 1,230	$ 1,200	$ 7,798	[1]	$ 6,146	$ 5,500	$ 1,987	$ 21,154	$ 21,431	$ 27,302
Earnings Per Share, Diluted	$ 0.82	[1]	$ 0.31	$ 0.07	$ 0.07	$ 0.48	[1]	$ 0.38	$ 0.31	$ 0.10	$ 1.28	$ 1.23	$ 1.30
Advertising Expense											$ 700	$ 600	$ 500
Self Insurance Reserve, Noncurrent	$ 32,225					$ 32,092					32,225	32,092
Insurance Settlements Receivable, Noncurrent	14,295					14,692					14,295	14,692
Income tax expense											3,486	16,914	$ 16,997
Retained Earnings (Accumulated Deficit)	143,241					$ 123,345					143,241	$ 123,345
Significant Change Orders Or Claims [Member]
Organization Consolidation and Presentation of Financial Statements [Line Items]
Revenues											13,700
New Accounting Pronouncement, Early Adoption, Effect [Member]
Organization Consolidation and Presentation of Financial Statements [Line Items]
Income tax expense											800
Maximum [Member]
Organization Consolidation and Presentation of Financial Statements [Line Items]
Loss Contingency Insurance Policy Deductible for Each Line of Coverage Excluding Wildfire and Health	1,000										1,000
Loss Contingency Insurance Policy Deductible for Wildfire	2,000										2,000
Loss Contingency Health Insurance Deductible For Qualified Individuals	$ 200										$ 200
Accounts Receivable [Member]
Organization Consolidation and Presentation of Financial Statements [Line Items]
Concentration Risk, Percentage												11.20%
Accounts Receivable [Member] | Number of Customers [Member]
Organization Consolidation and Presentation of Financial Statements [Line Items]
Concentration Risk, Percentage											10.00%	10.00%
Revenues [Member]
Organization Consolidation and Presentation of Financial Statements [Line Items]
Concentration Risk, Percentage											40.40%	46.40%	44.60%
Revenues [Member] | Number of Customers [Member] | Customer concentration risk [Member]
Organization Consolidation and Presentation of Financial Statements [Line Items]
Concentration Risk, Percentage												10.00%	10.00%
Labor employees covered by collective bargaining agreements [Member] | Labor Force Concentration Risk [Member]
Organization Consolidation and Presentation of Financial Statements [Line Items]
Concentration Risk, Percentage											91.00%
Sales Revenue, Net [Member] | TD customer [Member] | Customer concentration risk [Member]
Organization Consolidation and Presentation of Financial Statements [Line Items]
Concentration Risk, Percentage											10.70%
Restatement Adjustment [Member]
Organization Consolidation and Presentation of Financial Statements [Line Items]
Retained Earnings (Accumulated Deficit)														$ 200
Estimate Adjustment [Member]
Organization Consolidation and Presentation of Financial Statements [Line Items]
Cost Estimate Revision Gross Margin Increase (Decrease) Percentage											(0.70%)	(0.20%)	0.50%
Operating Income (Loss)											$ (10,400)	$ (2,600)	$ 5,900
Net Income (Loss) Attributable to Parent											$ (6,200)	$ (1,400)	$ 3,600
Earnings Per Share, Diluted											$ (0.38)	$ (0.08)	$ 0.17

[1] Results for the fourth quarter of 2017 include a net Tax Act benefit of $7.8 million, or $0.48 and $0.47 per basic and diluted share, respectively. See further discussion in Note 10 — Income Taxes to our Financial Statements.