Financial Information for Subsidiary Guarantor and Subsidiary Non- Guarantor - Supplemental Condensed Consolidating Statements of Cash Flows (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Condensed Financial Statements, Captions [Line Items]
NET CASH PROVIDED BY OPERATING ACTIVITIES:	$ 243,947	$ 290,608
CASH FLOWS FROM INVESTING ACTIVITIES:
Business acquisitions	(77,264)	(211,531)
Purchase of property and equipment	(87,860)	(80,538)
Other	(163)	102
Net cash flows from investing activities	(165,287)	(291,967)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from revolving credit and accounts receivable securitization facilities	305,800	604,500
Payments on revolving credit and accounts receivable securitization facilities	(305,800)	(604,500)
Proceeds from new term loan facility	970,000
Payments on term loan facility	(448,434)
Dividends paid	(510,634)
Debt issuance costs	(27,498)	(739)
Principal repayments on long-term obligations	(13,993)	(17,201)
Proceeds from stock options exercised including excess tax benefits	8,248	128
Repurchase of common stock	(1,488)	(4,829)
Payments of capital lease obligations	(44)	(701)
Other		(611)
Net cash flows from financing activities	(23,843)	(23,342)
EFFECT OF EXCHANGE RATES ON CASH AND CASH EQUIVALENTS	264	1,716
NET CHANGE IN CASH AND CASH EQUIVALENTS	55,081	(22,985)
CASH AND CASH EQUIVALENTS, Beginning of period	93,836	97,793
CASH AND CASH EQUIVALENTS, End of period	148,917	74,808
Parent / Issuer [Member]
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(6,873)	(6,939)
Net cash flows from investing activities	(6,873)	(6,939)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from revolving credit and accounts receivable securitization facilities	133,300	342,500
Payments on revolving credit and accounts receivable securitization facilities	(133,300)	(342,500)
Proceeds from new term loan facility	335,038
Payments on term loan facility	(68,476)
Dividends paid	(510,634)
Debt issuance costs	(27,498)
Principal repayments on long-term obligations	(3,346)	(5,327)
Proceeds from stock options exercised including excess tax benefits	8,248
Repurchase of common stock	(1,488)	(4,829)
Payments of capital lease obligations		(628)
Other		(611)
Net cash flows from financing activities	(268,156)	(11,395)
Intercompany	326,704	20,444
NET CHANGE IN CASH AND CASH EQUIVALENTS	51,675	2,110
CASH AND CASH EQUIVALENTS, Beginning of period	10,503
CASH AND CASH EQUIVALENTS, End of period	62,178	2,110
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
NET CASH PROVIDED BY OPERATING ACTIVITIES:	174,824	293,347
CASH FLOWS FROM INVESTING ACTIVITIES:
Business acquisitions	(77,204)	(185,845)
Purchase of property and equipment	(62,808)	(62,972)
Other	(163)	95
Net cash flows from investing activities	(140,175)	(248,722)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from new term loan facility	634,962
Payments on term loan facility	(379,958)
Principal repayments on long-term obligations	(10,647)	(11,874)
Payments of capital lease obligations	(28)	(47)
Net cash flows from financing activities	244,329	(11,921)
Intercompany	(278,978)	(32,704)
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
NET CASH PROVIDED BY OPERATING ACTIVITIES:	74,311	8,795
CASH FLOWS FROM INVESTING ACTIVITIES:
Business acquisitions	(60)	(25,686)
Purchase of property and equipment	(18,179)	(10,627)
Other		7
Net cash flows from investing activities	(18,239)	(36,306)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from revolving credit and accounts receivable securitization facilities	172,500	262,000
Payments on revolving credit and accounts receivable securitization facilities	(172,500)	(262,000)
Payments of capital lease obligations	(16)	(26)
Net cash flows from financing activities	(16)	(26)
Intercompany	(53,965)	7,668
EFFECT OF EXCHANGE RATES ON CASH AND CASH EQUIVALENTS	264	1,716
NET CHANGE IN CASH AND CASH EQUIVALENTS	2,355	(18,153)
CASH AND CASH EQUIVALENTS, Beginning of period	89,572	102,385
CASH AND CASH EQUIVALENTS, End of period	91,927	84,232
Eliminations and Consolidating Entries [Member]
Condensed Financial Statements, Captions [Line Items]
NET CASH PROVIDED BY OPERATING ACTIVITIES:	(5,188)	(11,534)
CASH FLOWS FROM FINANCING ACTIVITIES:
Intercompany	6,239	4,592
NET CHANGE IN CASH AND CASH EQUIVALENTS	1,051	(6,942)
CASH AND CASH EQUIVALENTS, Beginning of period	(6,239)	(4,592)
CASH AND CASH EQUIVALENTS, End of period	$ (5,188)	$ (11,534)