Financial Information for Subsidiary Guarantor and Subsidiary Non- Guarantor - Supplemental Condensed Consolidating Statements of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Condensed Financial Statements, Captions [Line Items]
NET CASH FLOWS FROM OPERATING ACTIVITIES:	$ 98,666	$ 91,663
CASH FLOWS USED IN INVESTING ACTIVITIES:
Business acquisitions	(13)	(76,579)
Purchase of property and equipment	(33,542)	(34,073)
Other	(408)
Net cash flows used in investing activities	(33,963)	(110,652)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from initial public offering, net of offering costs	400,464
Proceeds from revolving credit facilities	50,000	71,100
Proceeds and net settlemfrom stock options exercised including excess tax benefits	(689)	300
Payments on revolving credit facilities		(47,200)
Principal payments on long-term obligations	(10,062)	(3,856)
Payment of deferred financing and other debt-related costs	(29,972)	(7)
Payments on capital lease obligations		(20)
Dividends paid	(158)
Other		242
Other	(2)	(20)
Net cash flows from (used in) financing activities	409,581	20,266
EFFECT OF EXCHANGE RATES ON CASH AND CASH EQUIVALENTS	(2,259)	2,748
NET CHANGE IN CASH AND CASH EQUIVALENTS	472,025	4,025
CASH AND CASH EQUIVALENTS, Beginning of period	179,111	93,836
CASH AND CASH EQUIVALENTS, End of period	651,136	97,861
Parent / Issuer [Member]
CASH FLOWS USED IN INVESTING ACTIVITIES:
Purchase of property and equipment	(899)	(3,232)
Net cash flows used in investing activities	(899)	(3,232)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from initial public offering, net of offering costs	400,464
Proceeds from revolving credit facilities		27,600
Proceeds and net settlemfrom stock options exercised including excess tax benefits	(689)
Payments on revolving credit facilities		(27,600)
Principal payments on long-term obligations	(3,474)	(589)
Payment of deferred financing and other debt-related costs	(29,972)
Dividends paid	(158)
Other		242
Other	(2)
Net cash flows from (used in) financing activities	366,169	(347)
Intercompany	70,265	(4,912)
NET CHANGE IN CASH AND CASH EQUIVALENTS	435,535	(8,491)
CASH AND CASH EQUIVALENTS, Beginning of period	106,010	10,503
CASH AND CASH EQUIVALENTS, End of period	541,545	2,012
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
NET CASH FLOWS FROM OPERATING ACTIVITIES:	101,448	75,850
CASH FLOWS USED IN INVESTING ACTIVITIES:
Business acquisitions		(76,564)
Purchase of property and equipment	(22,519)	(25,857)
Other	(408)
Net cash flows used in investing activities	(22,927)	(102,421)
CASH FLOWS FROM FINANCING ACTIVITIES:
Principal payments on long-term obligations	(6,588)	(3,267)
Payments on capital lease obligations		(9)
Net cash flows from (used in) financing activities	(6,588)	(3,276)
Intercompany	(73,444)	29,922
NET CHANGE IN CASH AND CASH EQUIVALENTS	(1,511)	75
CASH AND CASH EQUIVALENTS, Beginning of period	1,821
CASH AND CASH EQUIVALENTS, End of period	310	75
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
NET CASH FLOWS FROM OPERATING ACTIVITIES:	(2,782)	15,813
CASH FLOWS USED IN INVESTING ACTIVITIES:
Business acquisitions	(13)	(15)
Purchase of property and equipment	(10,124)	(4,984)
Net cash flows used in investing activities	(10,137)	(4,999)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from revolving credit facilities	50,000	43,500
Payments on revolving credit facilities		(19,600)
Payments on capital lease obligations		(11)
Net cash flows from (used in) financing activities	50,000	23,889
Intercompany	3,179	(31,249)
EFFECT OF EXCHANGE RATES ON CASH AND CASH EQUIVALENTS	(2,259)	2,748
NET CHANGE IN CASH AND CASH EQUIVALENTS	38,001	6,202
CASH AND CASH EQUIVALENTS, Beginning of period	71,280	89,572
CASH AND CASH EQUIVALENTS, End of period	109,281	95,774
Eliminations and Consolidating Entries [Member]
Condensed Financial Statements, Captions [Line Items]
NET CASH FLOWS FROM OPERATING ACTIVITIES:
CASH FLOWS USED IN INVESTING ACTIVITIES:
Business acquisitions
Purchase of property and equipment
Other
Net cash flows used in investing activities
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from initial public offering, net of offering costs
Proceeds from revolving credit facilities
Proceeds and net settlemfrom stock options exercised including excess tax benefits
Principal payments on long-term obligations
Payment of deferred financing and other debt-related costs
Dividends paid
Other
Net cash flows from (used in) financing activities
Intercompany		6,239
EFFECT OF EXCHANGE RATES ON CASH AND CASH EQUIVALENTS
NET CHANGE IN CASH AND CASH EQUIVALENTS		6,239
CASH AND CASH EQUIVALENTS, Beginning of period		(6,239)
CASH AND CASH EQUIVALENTS, End of period