Construction Joint Ventures (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2016 USD ($)
Construction Joint Venture
Line Item Revenue	$ 226,849	$ 209,487
Net cash provided (used in) operating activities	13,336	(10,434)
Unconsolidated Construction Joint Venture
Construction Joint Venture
Performance Guarantees	83,100	77,400	$ 83,100
Partnership Interest [Member] | Unconsolidated Construction Joint Venture
Construction Joint Venture
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	$ 4,600,000
Joint Venture Consolidated | Consolidated Construction Joint Venture
Construction Joint Venture
Number of Active Joint Venture Projects	5
Line Item Revenue	$ 35,500	22,200
Joint Venture Unconsolidated | Unconsolidated Construction Joint Venture
Construction Joint Venture
Number of Active Joint Venture Projects	10
Joint Venture Unconsolidated | Line Item Joint Venture
Construction Joint Venture
Number of Active Joint Venture Projects	2
Line Item Revenue	$ 8,000	4,400
Reporting Entitys Interest in Joint Venture [Member] | Unconsolidated Construction Joint Venture
Construction Joint Venture
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	1,400,000
Other Partners Interest in Partnerships [Member] | Unconsolidated Construction Joint Venture
Construction Joint Venture
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	3,200,000
Minimum | Joint Venture Consolidated | Consolidated Construction Joint Venture
Construction Joint Venture
Construction Contract Value	48,200
Revenue Remaining to be Recognized on Consolidated Construction Joint Ventures	$ 3,200
Proportionate Share of the Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	50.00%
Net cash provided (used in) operating activities	$ (6,500)	$ (3,800)
Minimum | Joint Venture Unconsolidated | Unconsolidated Construction Joint Venture
Construction Joint Venture
Construction Contract Value	$ 78,800
Proportionate Share of the Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	20.00%
Minimum | Joint Venture Unconsolidated | Line Item Joint Venture
Construction Joint Venture
Construction Contract Value	$ 66,200
Revenue Per Project Remaining to be Recognized on Line Item Construction Joint Ventures	10,600
Minimum | Reporting Entitys Interest in Joint Venture [Member] | Unconsolidated Construction Joint Venture
Construction Joint Venture
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	700
Minimum | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture
Construction Joint Venture
Construction Contract Value	44,700
Maximum | Joint Venture Consolidated | Consolidated Construction Joint Venture
Construction Joint Venture
Construction Contract Value	292,400
Revenue Remaining to be Recognized on Consolidated Construction Joint Ventures	$ 157,800
Proportionate Share of the Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	65.00%
Maximum | Joint Venture Unconsolidated | Unconsolidated Construction Joint Venture
Construction Joint Venture
Construction Contract Value	$ 3,600,000
Proportionate Share of the Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	50.00%
Maximum | Joint Venture Unconsolidated | Line Item Joint Venture
Construction Joint Venture
Construction Contract Value	$ 75,800
Revenue Per Project Remaining to be Recognized on Line Item Construction Joint Ventures	1,100
Maximum | Reporting Entitys Interest in Joint Venture [Member] | Unconsolidated Construction Joint Venture
Construction Joint Venture
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	475,700
Maximum | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture
Construction Joint Venture
Construction Contract Value	$ 28,700