Acquisitions - Preliminary Purchase Price Allocation (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Business Acquisition [Line Items]
Identifiable intangible assets:	$ 48,570	$ 49,370
Goodwill	53,799	55,419
Kenny
Business Acquisition [Line Items]
Cash and cash equivalents	53,185
Receivables	88,725
Costs and estimated earnings in excess of billings	444
Inventories	731
Equity in construction joint ventures	7,803
Other current assets	6,039
Property and equipment, net	51,909
Customer relationships	2,200
Total amount allocated to identifiable intangible assets	14,200
Accounts payable	43,591
Billings in excess of costs and estimated earnings	50,098
Accrued expenses and other current liabilities	16,806
Non-controlling interests	15,326
Total identifiable net assets acquired	97,215
Goodwill	43,899
Total purchase price	$ 141,114