Summary of Significant Accounting Policies (Details) - USD ($)		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Significant Accounting Policies [Line Items]
Restructuring and impairment (gains) charges, net		$ (6,003,000)	$ (2,643,000)	$ 52,139,000
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Revenue		48,500,000
Real estate held for development and sale		500,000	11,609,000
Goodwill		53,799,000	53,799,000
Cash and cash equivalents		252,836,000	255,961,000	229,121,000	$ 321,990,000
Capitalized Computer Software, Additions		2,300,000	4,100,000	2,500,000
Change in Loss Assumptions, Potential Effect on Operating Results and Financial Position		1,000,000
New Accounting Pronouncement, Early Adoption, Effect [Member]
Significant Accounting Policies [Line Items]
Current deferred tax assets			53,200,000
Long-term deferred tax liabilities			20,400,000
Minimum [Member]
Significant Accounting Policies [Line Items]
Workers' Compensation Liability		500,000
Maximum [Member]
Significant Accounting Policies [Line Items]
Workers' Compensation Liability		$ 1,000,000
Software Development [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life		3 years
Software Development [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Property, Plant and Equipment, Useful Life		5 years
Consolidated Construction Joint Venture [Member] | Joint Venture Consolidated [Member]
Significant Accounting Policies [Line Items]
Cash and cash equivalents	[1]	$ 46,210,000	61,276,000
Consolidated Construction Joint Venture [Member] | Joint Venture Consolidated [Member] | Minimum [Member]
Significant Accounting Policies [Line Items]
Contract Value of Active Construction Joint Venture Projects		1,500,000
Consolidated Construction Joint Venture [Member] | Joint Venture Consolidated [Member] | Maximum [Member]
Significant Accounting Policies [Line Items]
Contract Value of Active Construction Joint Venture Projects		293,800,000
Unconsolidated Construction Joint Venture [Member] | Reporting Entitys Interest in Joint Venture [Member]
Significant Accounting Policies [Line Items]
Contract Value of Active Construction Joint Venture Projects		1,600,000,000
Unconsolidated Construction Joint Venture [Member] | Other Partners Interest in Joint Venture [Member]
Significant Accounting Policies [Line Items]
Contract Value of Active Construction Joint Venture Projects		3,500,000,000
Enterprise Improvement Plan [Member]
Significant Accounting Policies [Line Items]
Restructuring and impairment (gains) charges, net		(6,003,000)	(1,283,000)	48,975,000
Enterprise Improvement Plan [Member] | Restructuring Type, Real Estate Asset Impairment [Member]
Significant Accounting Policies [Line Items]
Restructuring and impairment (gains) charges, net		(4,959,000)	0	31,090,000
Noncontrolling Interest [Member] | Enterprise Improvement Plan [Member] | Restructuring Type, Real Estate Asset Impairment [Member]
Significant Accounting Policies [Line Items]
Restructuring and impairment (gains) charges, net		3,300,000		3,900,000
Customer [Member]
Significant Accounting Policies [Line Items]
Litigation Settlement, Amount		3,800,000	26,600,000
Non-customer [Member]
Significant Accounting Policies [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Change on Net Revenue		7,000,000
Litigation Settlement, Amount		$ 0	7,900,000
To Align With Other Selling Costs [Member] | Selling, General and Administrative Expenses [Member]
Significant Accounting Policies [Line Items]
Prior period reclassification adjustment			1,200,000	800,000
To Align With Associated Salaries And Related Benefits [Member] | Selling, General and Administrative Expenses [Member]
Significant Accounting Policies [Line Items]
Prior period reclassification adjustment			$ (9,300,000)	$ (8,900,000)

[1] The volume and stage of completion of contracts from our consolidated construction joint ventures may cause fluctuations in cash and cash equivalents as well as billings in excess of costs and estimated earnings and costs in excess of billings and estimated earnings between periods.