Business Segments (Reportable Segments) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Business Segments [Line items]
Revenue		$ 958,487	$ 1,028,156
INCOME (LOSS) FROM CONSTRUCTION OPERATIONS		22,913	(925)	[1]
Capital expenditures		14,412	19,970
Depreciation and amortization	[2]	13,717	10,187
External And Intersegment Customers [Member]
Business Segments [Line items]
Revenue		1,011,392	1,090,818
Elimination Of Intersegment Revenues [Member]
Business Segments [Line items]
Revenue		(52,905)	(62,662)
Reportable Segments [Member]
Business Segments [Line items]
Revenue		958,487	1,028,156
INCOME (LOSS) FROM CONSTRUCTION OPERATIONS		37,390	16,499	[1]
Capital expenditures		14,190	19,893
Depreciation and amortization	[2]	10,937	7,349
Reportable Segments [Member] | External And Intersegment Customers [Member]
Business Segments [Line items]
Revenue		1,011,392	1,090,818
Reportable Segments [Member] | Elimination Of Intersegment Revenues [Member]
Business Segments [Line items]
Revenue		(52,905)	(62,662)
Civil [Member]
Business Segments [Line items]
Revenue		333,494	263,114
INCOME (LOSS) FROM CONSTRUCTION OPERATIONS		41,745	2,839	[1]
Capital expenditures		14,012	19,196
Depreciation and amortization	[2]	9,370	5,756
Civil [Member] | External And Intersegment Customers [Member]
Business Segments [Line items]
Revenue		383,622	325,400
Civil [Member] | Elimination Of Intersegment Revenues [Member]
Business Segments [Line items]
Revenue		(50,128)	(62,286)
Building [Member]
Business Segments [Line items]
Revenue		433,466	490,241
INCOME (LOSS) FROM CONSTRUCTION OPERATIONS		3,133	6,425	[1]
Capital expenditures		55	278
Depreciation and amortization	[2]	503	481
Building [Member] | External And Intersegment Customers [Member]
Business Segments [Line items]
Revenue		436,243	490,617
Building [Member] | Elimination Of Intersegment Revenues [Member]
Business Segments [Line items]
Revenue		(2,777)	(376)
Specialty Contractors [Member]
Business Segments [Line items]
Revenue		191,527	274,801
INCOME (LOSS) FROM CONSTRUCTION OPERATIONS		(7,488)	7,235	[1]
Capital expenditures		123	419
Depreciation and amortization	[2]	1,064	1,112
Specialty Contractors [Member] | External And Intersegment Customers [Member]
Business Segments [Line items]
Revenue		191,527	274,801
Corporate [Member]
Business Segments [Line items]
INCOME (LOSS) FROM CONSTRUCTION OPERATIONS	[3]	(14,477)	(17,424)	[1]
Capital expenditures		222	77
Depreciation and amortization	[2]	$ 2,780	$ 2,838

[1] During the three months ended March 31, 2018, the Company recorded a charge of $17.8 million in income from construction operations (an after-tax impact of $12.8 million, or $0.25 per diluted share), which was primarily non-cash, as a result of the unexpected outcome of an arbitration decision related to a subcontract back charge dispute on a Civil segment project in New York that was completed in 2013.

[2] Depreciation and amortization is included in income (loss) from construction operations.

[3] Consists primarily of corporate general and administrative expenses.