Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
	Jun. 30, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Historical Cost	$ 56,400	$ 56,400
Accumulated Amortization	(9,915)	(6,652)
Net Balance	46,485	49,748
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Useful Life	9 years	9 years
Historical Cost	50,000	50,000
Accumulated Amortization	(8,460)	(5,682)
Net Balance	41,540	44,318
Tradenames and trademarks
Finite-Lived Intangible Assets [Line Items]
Useful Life	10 years	10 years
Historical Cost	5,300	5,300
Accumulated Amortization	(795)	(530)
Net Balance	4,505	4,770
Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Useful Life	2 years 6 months	2 years 6 months
Historical Cost	1,100	1,100
Accumulated Amortization	(660)	(440)
Net Balance	$ 440	$ 660