Summary of Significant Accounting Policies - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property, Plant and Equipment [Line Items]
Unbilled receivables for unapproved change orders	$ 13,800,000	$ 14,500,000
Claims on uncompleted contracts	700,000	1,600,000
Accounts receivable, unapproved contract claims	800,000	200,000
Accouts receivable, contractually billed amounts on contracts related to unapproved contract claims	41,000,000	40,400,000
Accounts receivable, retainage	178,600,000	188,100,000
Accounts receivable, retainage estimated to be collected in 2013	77.00%
Accounts payable, retainage	39,700,000	39,500,000
Accounts payable, retainage estimated to be paid in 2013	86.00%
Accounts receivable, net	1,221,956,000	1,187,832,000
Allowance for doubtful accounts	11,472,000	16,685,000
Provision for (recovery of) doubtful accounts	1,163,000	2,238,000	(5,126,000)
Insurance liabilities, current	25,500,000	23,700,000
Insurance liabilities, noncurrent	$ 108,100,000	$ 104,900,000
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