Accounts Payable and Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accounts Payable and Accrued Liabilities
Retention amounts included in accounts payable	$ 10,562	$ 8,375
Accrued expenses and other current liabilities
Payroll and related employee benefits	42,718	33,358
Insurance, including self-insurance reserves	42,546	44,695
Reserve for estimated losses on uncompleted contracts	12,801	7,261
Corporate income taxes and other taxes	3,368	2,447
Accrued administrative cost	3,791	1,415
Other	2,782	4,420
Total accrued expenses and other current liabilities	$ 108,006	$ 93,596