Summary of Significant Accounting Policies - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Settlement of contract claim	$ 12,100,000	$ 12,100,000	$ 0
Unbilled revenues for unapproved change orders	18,900,000	18,900,000	18,800,000
Claims on uncompleted contracts	900,000	900,000	3,000,000
Accounts receivable, unapproved contract claims	300,000	300,000	2,300,000
Accounts receivable, contractually billed amounts on contracts related to unapproved contract claims	52,000,000	52,000,000	54,000,000
Accounts receivable, retainage	189,200,000	$ 189,200,000	177,800,000
Accounts receivable, retainage estimated to be collected in next fiscal year		85.00%
Accounts payable, retainage	34,600,000	$ 34,600,000	35,700,000
Accounts payable, retainage estimated to be paid in next fiscal year		90.00%
Accounts receivable, net	1,359,862,000	$ 1,359,862,000	1,234,187,000
Allowance for doubtful accounts	11,175,000	11,175,000	10,424,000
Provision for doubtful accounts		2,853,000	2,918,000	$ 3,533,000
Non-cash expense for impairment of property, plant and equipment		$ 0	0	$ 0
Minimum
Property, Plant and Equipment [Line Items]
Contract terms		1 month
Maximum
Property, Plant and Equipment [Line Items]
Contract terms		4 years
Buildings
Property, Plant and Equipment [Line Items]
Estimated useful life		25 years
Machinery and Equipment | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life		3 years
Machinery and Equipment | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life		10 years
Vehicles, Furniture and Fixtures, and Computer Hardware and Software | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful life		3 years
Vehicles, Furniture and Fixtures, and Computer Hardware and Software | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful life		7 years
Other Current Liabilities
Property, Plant and Equipment [Line Items]
Insurance liabilities, current	29,900,000	$ 29,900,000	28,800,000
Other Noncurrent Liabilities
Property, Plant and Equipment [Line Items]
Insurance liabilities, noncurrent	$ 114,300,000	$ 114,300,000	$ 106,300,000