Goodwill and Other Intangible Assets (Detail of Intangible Assets Classified as Other Long-Term Assets) (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2011	Dec. 31, 2010
Other intangible assets useful life	12.2
Cost	$ 584,375	$ 563,483
Accumulated Amortization	190,050	164,009
Net	394,325	399,474
Customer Contracts/Relationships [Member]
Other intangible assets useful life	10.7
Cost	417,285	413,855
Accumulated Amortization	165,807	145,997
Net	251,478	267,858
Trade Names [Member]
Other intangible assets useful life	19.6
Cost	87,400	87,400
Accumulated Amortization	4,565	2,268
Net	82,835	85,132
Provider Contracts [Member]
Other intangible assets useful life	16.0
Cost	42,753	42,753
Accumulated Amortization	13,347	11,659
Net	29,406	31,094
Noncompetes and Other [Member]
Other intangible assets useful life	7.4
Cost	36,937	19,475
Accumulated Amortization	6,331	4,085
Net	$ 30,606	$ 15,390