Revisions in Estimates (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Dec. 31, 2015 USD ($) project	Dec. 31, 2014 USD ($) project	Dec. 31, 2013 USD ($) project
Change in Accounting Estimate [Line Items]
Initial gross profit impact from projects exceeding threshold	$ 102,008,000	$ 96,253,000	$ 65,045,000	$ 40,052,000	$ 73,726,000	$ 66,292,000	$ 80,729,000	$ 21,499,000	$ 303,358,000	$ 242,247,000	$ 177,177,000
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Revenue									48,500,000
Financial Effect on Future Periods	0								0
Amount Considered Significant on Individual Project Gross Profit	$ 1,000,000									1,000,000
Construction [Member]
Change in Accounting Estimate [Line Items]
Increase (Decrease) on Project Profitability									$ (19,900,000)	(7,300,000)	(1,700,000)
Construction Contract Backlog, Percent	0.90%								0.90%
Construction [Member] | Maximum [Member]
Change in Accounting Estimate [Line Items]
Total Contract Value	$ 75,000,000								$ 75,000,000
Large Project Construction [Member] | Minimum [Member]
Change in Accounting Estimate [Line Items]
Total Contract Value	$ 75,000,000								75,000,000
Contracts Accounted for under Percentage of Completion [Member] | Large Project Construction [Member]
Change in Accounting Estimate [Line Items]
Increase (Decrease) on Project Profitability									(7,600,000)	(46,900,000)	(25,500,000)
Contracts Accounted for under Percentage of Completion [Member] | Large Project Construction [Member] | Noncontrolling Interest [Member]
Change in Accounting Estimate [Line Items]
Increase (Decrease) on Project Profitability									(3,000,000)	(9,500,000)	5,600,000
Upward Estimate Change [Member] | Construction [Member]
Change in Accounting Estimate [Line Items]
Initial gross profit impact from projects exceeding threshold									25,800,000	74,700,000	9,100,000
Increase (Decrease) on Project Profitability									$ (30,700,000)	$ (9,200,000)	$ (16,100,000)
Number of Projects with Estimate Changes | project									14	7	6
Upward Estimate Change [Member] | Construction [Member] | Minimum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit									$ (1,100,000)	$ (1,000,000)	$ (1,100,000)
Upward Estimate Change [Member] | Construction [Member] | Maximum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit									(6,500,000)	(1,800,000)	(3,700,000)
Upward Estimate Change [Member] | Large Project Construction [Member]
Change in Accounting Estimate [Line Items]
Increase (Decrease) on Project Profitability									$ (27,900,000)	$ (66,800,000)	$ (77,500,000)
Number of Projects with Estimate Changes | project									7	12	7
Upward Estimate Change [Member] | Large Project Construction [Member] | Minimum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit									$ (1,500,000)	$ (1,000,000)	$ (2,600,000)
Upward Estimate Change [Member] | Large Project Construction [Member] | Maximum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit									(6,700,000)	(15,200,000)	(41,300,000)
Downward Estimate Change [Member] | Construction [Member]
Change in Accounting Estimate [Line Items]
Increase (Decrease) on Project Profitability									$ 10,800,000	$ 16,500,000	$ 17,800,000
Number of Projects with Estimate Changes | project									5	6	5
Downward Estimate Change [Member] | Construction [Member] | Minimum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit									$ 1,200,000	$ 1,600,000	$ 1,200,000
Downward Estimate Change [Member] | Construction [Member] | Maximum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit									3,300,000	4,100,000	7,400,000
Downward Estimate Change [Member] | Large Project Construction [Member]
Change in Accounting Estimate [Line Items]
Increase (Decrease) on Project Profitability									$ 20,300,000	$ 19,900,000	$ 52,000,000
Number of Projects with Estimate Changes | project									6	3	5
Downward Estimate Change [Member] | Large Project Construction [Member] | Minimum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit									$ 1,000,000	$ 1,100,000	$ 1,900,000
Downward Estimate Change [Member] | Large Project Construction [Member] | Maximum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit									$ 5,500,000	$ 16,800,000	$ 26,800,000
Complete or Substantially Complete [Member] | Downward Estimate Change [Member] | Construction [Member]
Change in Accounting Estimate [Line Items]
Number of Projects with Estimate Changes | project									4
Construction Project In Progress, Percent Complete	81.70%								81.70%
No Material Associated Cost [Member] | Customer [Member]
Change in Accounting Estimate [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Revenue									$ 9,700,000
Revisions to Estimated Total Contract Costs [Member] | Customer [Member]
Change in Accounting Estimate [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Revenue									$ 38,800,000