Goodwill and Other Intangible Assets - Summary of Other Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jan. 01, 2012
Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	$ 36,700	$ 36,700
Accumulated Amortization	(27,016)	(23,935)
Carrying Value	9,684	12,765	22,907
Project Backlog [Member]
Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	16,459	16,459
Accumulated Amortization	(15,955)	(15,764)
Carrying Value	504	695
Customer Contracts and Related Relationships [Member]
Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	15,460	15,460
Accumulated Amortization	(6,588)	(4,030)
Carrying Value	8,872	11,430
Non-compete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	3,671	3,671
Accumulated Amortization	(3,465)	(3,233)
Carrying Value	206	438
Trademark/Trade Name [Member]
Finite-Lived Intangible Assets [Line Items]
Acquisition Date Fair Value	1,110	1,110
Accumulated Amortization	(1,008)	(908)
Carrying Value	$ 102	$ 202