Other Intangible Assets, Net (Schedule of Finite-Lived Intangible Assets by Major Class) (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, gross	$ 360,455,000		$ 360,455,000		$ 323,281,000
Less accumulated amortization	(176,476,000)		(176,476,000)		(151,697,000)
Total	183,979,000		183,979,000		171,584,000
Amortization expense for finite-lived intangible assets	9,100,000	7,100,000	26,300,000	20,500,000
Customer Lists [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, gross	320,432,000		320,432,000		286,164,000
Less accumulated amortization	(159,669,000)		(159,669,000)		(137,782,000)
Total	160,763,000		160,763,000		148,382,000
Noncompete Agreements [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, gross	9,156,000		9,156,000		9,264,000
Less accumulated amortization	(6,331,000)		(6,331,000)		(5,438,000)
Total	2,825,000		2,825,000		3,826,000
Trade Names [Member]
Finite-Lived Intangible Assets [Line Items]
Other intangible assets, gross	30,867,000		30,867,000		27,853,000
Less accumulated amortization	(10,476,000)		(10,476,000)		(8,477,000)
Total	$ 20,391,000		$ 20,391,000		$ 19,376,000