Description of Business and Summary of Significant Accounting Policies (Details) (USD $)	3 Months Ended									12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012		Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012 Segment	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Nature of Business [Abstract]
Number of reportable segments										4
Basis of Presentation [Abstract]
Increase (decrease) in cash flows provided by operating activities										$ (67,863,000)	$ (31,620,000)	$ 25,542,000
Increase (decrease) in cash flows provided by investing activities										(16,855,000)	(375,221,000)	(70,797,000)
Increase (decrease) in cash flows provided by financing activities										48,534,000	139,703,000	168,324,000
Change in Accounting Estimate [Abstract]
Increase in estimated recovery of project costs										12,400,000
Income from Construction Operations	60,724,000	54,676,000	(354,174,000)	[1]	16,963,000	50,792,000	62,036,000	37,035,000	18,513,000	(221,811,000)	168,376,000	172,312,000
Net Income (Loss)	41,635,000	42,591,000	(348,423,000)		(1,203,000)	24,048,000	35,477,000	19,694,000	6,929,000	(265,400,000)	86,148,000	103,500,000
Diluted Earnings (Loss) per Common Share (in dollars per share)	$ 0.86	$ 0.88	$ (7.35)		$ (0.03)	$ 0.50	$ 0.74	$ 0.41	$ 0.14	$ (5.59)	$ 1.80	$ 2.13
Costs and Estimated Earnings in Excess of Billings [Abstract]
Unbilled costs and profits incurred to date	157,119,000					107,645,000				157,119,000	107,645,000
Unapproved change orders	141,596,000					136,704,000				141,596,000	136,704,000
Claims	166,287,000					114,049,000				166,287,000	114,049,000
Costs and estimated earnings in excess of billings	465,002,000					358,398,000				465,002,000	358,398,000
Unapproved change orders and claims subject to pending litigation	62,000,000					85,200,000				62,000,000	85,200,000
Costs and estimated earnings in excess of billings beyond one year	181,300,000									181,300,000
Cash and Cash Equivalents and Restricted Cash [Abstract]
Cash and cash equivalents	168,056,000					204,240,000				168,056,000	204,240,000	471,378,000	348,309,000
Restricted cash	38,717,000					35,437,000				38,717,000	35,437,000
Corporate Cash and Cash Equivalents [Member]
Cash and Cash Equivalents and Restricted Cash [Abstract]
Cash and cash equivalents	70,780,000					109,180,000				70,780,000	109,180,000
Company's Share of Joint Venture Cash and Cash Equivalents [Member]
Cash and Cash Equivalents and Restricted Cash [Abstract]
Cash and cash equivalents	97,276,000					95,060,000				97,276,000	95,060,000
Stock Options [Member]
Earnings (Loss) Per Common Share [Abstract]
Antidilutive securities excluded from computation of diluted earnings per share (in shares)										1,315,465	880,000	435,000
Restricted Stock Units [Member]
Earnings (Loss) Per Common Share [Abstract]
Antidilutive securities excluded from computation of diluted earnings per share (in shares)										1,291,665
Minimum [Member] | Auction Rate Securities [Member] | Income Approach Valuation Model [Member]
Long-term Investments [Abstract]
Fair value inputs, discount rate (in hundredths)										3.00%
Fair value inputs, term of auction rate securities (in years)										6 years
Maximum [Member] | Auction Rate Securities [Member] | Income Approach Valuation Model [Member]
Long-term Investments [Abstract]
Fair value inputs, discount rate (in hundredths)										7.00%
Fair value inputs, term of auction rate securities (in years)										8 years
Construction Equipment [Member] | Minimum [Member]
Property and Equipment [Abstract]
Estimated useful lives										5 years
Construction Equipment [Member] | Maximum [Member]
Property and Equipment [Abstract]
Estimated useful lives										20 years
Remaining Depreciable Property [Member] | Minimum [Member]
Property and Equipment [Abstract]
Estimated useful lives										3 years
Remaining Depreciable Property [Member] | Maximum [Member]
Property and Equipment [Abstract]
Estimated useful lives										40 years
Contracts Accounted for Under Percentage of Completion [Member]
Change in Accounting Estimate [Abstract]
Income from Construction Operations										12,400,000
Net Income (Loss)										7,500,000
Diluted Earnings (Loss) per Common Share (in dollars per share)										$ 0.16
Correction for Payments Related to Deferred Purchase Price Obligation of Previous Acquisitions [Member]
Basis of Presentation [Abstract]
Increase (decrease) in cash flows provided by operating activities											(1,100,000)	(700,000)
Increase (decrease) in cash flows provided by investing activities											3,000,000	6,700,000
Increase (decrease) in cash flows provided by financing activities											$ (1,900,000)	$ (6,000,000)

[1] Includes pre-tax goodwill and intangible asset impairment of $376.6 million.