Amortization Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization	$ (18,400)	$ (14,100)
Total Amortizable Intangible Assets	82,762
Customer Relationships
Finite-Lived Intangible Assets [Line Items]
Amortizable Intangible Assets	90,079	7,820
Accumulated Amortization	(16,267)
Noncompete Agreements
Finite-Lived Intangible Assets [Line Items]
Amortizable Intangible Assets	7,999	7,600
Accumulated Amortization	(1,948)
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Amortizable Intangible Assets	3,065	3,100
Accumulated Amortization	$ (166)