Goodwill and Other Intangible Assets - Gross Carrying Amounts and Accumulated Amortization Relating to Other Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Finite Lived Intangible Assets Net Of Amortization [Line Items]
Gross Carrying Amount	$ 243,148	$ 133,333
Accumulated Amortization	(43,349)	(31,178)
Net	199,799	102,155
Customer relationships [Member]
Finite Lived Intangible Assets Net Of Amortization [Line Items]
Gross Carrying Amount	209,328	100,921
Accumulated Amortization	(38,030)	(26,098)
Net	171,298	74,823
Trademarks [Member]
Finite Lived Intangible Assets Net Of Amortization [Line Items]
Gross Carrying Amount	29,337	26,996
Accumulated Amortization	(1,944)	(1,197)
Net	27,393	25,799
Non-competition agreements [Member]
Finite Lived Intangible Assets Net Of Amortization [Line Items]
Gross Carrying Amount	4,483	5,416
Accumulated Amortization	(3,375)	(3,883)
Net	$ 1,108	$ 1,533