Goodwill and Intangible Assets (Details) (USD $)	3 Months Ended		6 Months Ended			6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended			6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Jun. 30, 2012 Trade names (amortizable) [Member]	Dec. 31, 2011 Trade names (amortizable) [Member]	Jun. 30, 2012 Customer relationship [Member]	Dec. 31, 2011 Customer relationship [Member]	Jun. 30, 2012 Construction Contract Backlog [Member]	Dec. 31, 2011 Construction Contract Backlog [Member]	Jun. 30, 2012 Trade Names (Non-amortizable) [Member]	Dec. 31, 2011 Trade Names (Non-amortizable) [Member]	Jun. 30, 2012 Contractor License [Member]	Dec. 31, 2011 Contractor License [Member]	Jun. 30, 2012 Minimum [Member]	Jun. 30, 2012 Maximum [Member]	Jun. 30, 2012 Building Group [Member]	Jun. 30, 2012 Civil [Member]	Jun. 30, 2012 Management Services [Member]	Jun. 30, 2012 Specialty Contractors [Member]
Goodwill and Intangible Assets [Abstract]
Indefinite lived intangible assets impairment charge			$ 16,400,000
Finite lived intangible assets impairment charge			39,100,000
Goodwill [Line Items]
Weighted-average cost of capital rate (in hundredths)																15.00%	16.50%
Gross goodwill			1,059,500,000															420,267,000	430,762,000	66,638,000	141,833,000
Accumulated impairment			(166,898,000)															(146,847,000)	0	(20,051,000)	0
Balance at beginning of period			892,602,000															273,420,000	430,762,000	46,587,000	141,833,000
Acquisition related adjustment			(869,000)															0	(869,000)	0	0
Impairment charge			(321,087,000)															(262,918,000)	(55,740,000)	(2,429,000)	0
Balance at end of period	570,646,000		570,646,000															10,502,000	374,153,000	44,158,000	141,833,000
Indefinite-lived Intangible Assets [Line Items]
Cost												117,600,000	117,600,000	6,000,000	6,000,000
Accumulated amortization												0	0	0	0
Accumulated impairment charge												(67,190,000)	(56,100,000)	(6,000,000)	(680,000)
Carrying value												50,410,000	61,500,000	0	5,320,000
Weighted average amortization period												Indefinite	Indefinite	N/A	Indefinite
Finite-Lived Intangible Assets [Line Items]
Cost						74,350,000	74,350,000	39,800,000	39,800,000	73,706,000	71,140,000
Accumulated amortization						(2,610,000)	(788,000)	(12,387,000)	(10,585,000)	(49,677,000)	(41,938,000)
Accumulated impairment charge						(23,232,000)	(800,000)	(16,645,000)	0	0	0
Carrying value						48,508,000	72,762,000	10,768,000	29,215,000	24,029,000	29,202,000
Weighted average amortization period						20 years	20 years	11 years 4 months 24 days	11 years 7 months 6 days	2 years 10 months 24 days	2 years 10 months 24 days
Total intangible assets [Abstract]
Cost	311,456,000		311,456,000		308,890,000
Accumulated amortization	(64,674,000)		(64,674,000)		(53,311,000)
Accumulated impairment charge	(113,067,000)		(113,067,000)		(57,580,000)
Carrying value	133,715,000		133,715,000		197,999,000
Amortization Expense [Abstract]
Amortization expense during period	6,300,000	2,200,000	11,400,000	3,900,000
Amortization expense, remainder of 2012	6,900,000		6,900,000
Amortization expense, 2013	13,100,000		13,100,000
Amortization expense, 2014	11,900,000		11,900,000
Amortization expense, 2015	5,300,000		5,300,000
Amortization expense, 2016	3,500,000		3,500,000
Amortization expense, thereafter	$ 42,600,000		$ 42,600,000