Goodwill and Other Intangible Assets (Details 1) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Summary of other intangible assets
Acquisition Date Fair Value	$ 36,700	$ 36,700
Accumulated Amortization	(21,526)	(13,793)
Carrying Value	15,174	22,907
Project backlog [Member]
Summary of other intangible assets
Acquisition Date Fair Value	16,459	16,459
Accumulated Amortization	(13,987)	(8,657)
Carrying Value	2,472	7,802
Customer contracts and related relationships [Member]
Summary of other intangible assets
Acquisition Date Fair Value	15,460	15,460
Accumulated Amortization	(3,588)	(2,260)
Carrying Value	11,872	13,200
Non-compete agreements [Member]
Summary of other intangible assets
Acquisition Date Fair Value	3,671	3,671
Accumulated Amortization	(3,136)	(2,427)
Carrying Value	535	1,244
Trademark / trade name [Member]
Summary of other intangible assets
Acquisition Date Fair Value	1,110	1,110
Accumulated Amortization	(815)	(449)
Carrying Value	$ 295	$ 661