Supplemental Balance Sheet Information - Accrued Expenses (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Supplemental Balance Sheet Data [Abstract]
Vendor and other accrued expenses	$ 56,570	$ 49,499
Estimated casualty and healthcare liabilities	15,255	17,780
Job costs	12,403	13,718
Accrued compensation	22,184	21,033
Income tax payable and deferred income taxes	6,539	9,587
Total	$ 112,951	$ 111,617