Income Taxes (Significant Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets
Timing of expense recognition	$ 58,048	$ 47,017
Net operating losses	3,564	2,188
Other, net	114,225	6,980
Deferred tax assets	175,837	56,185
Valuation Allowance	(460)	(1,369)
Net deferred tax assets	175,377	54,816
Deferred Tax Liabilities
Intangible assets, due primarily to purchase accounting	(99,549)	(26,094)
Fixed assets, due primarily to purchase accounting	(101,022)	(90,886)
Construction contract accounting	(7,530)	(6,854)
Joint ventures - construction	(27,604)	(30,654)
Other	(62,494)	(10,012)
Deferred tax liabilities	(298,199)	(164,500)
Net deferred tax liabilities	(122,822)	(109,684)
Net Deferred Tax Liability
Current deferred tax asset	26,306	17,962
Long-term deferred tax asset	149,071	36,854
Current deferred tax liability	(24,889)	(14,129)
Long-term deferred tax liability	(273,310)	(150,371)
Net deferred tax liabilities	$ (122,822)	$ (109,684)