Summary of Significant Accounting Policies (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Amortizable intangible assets
Gross carrying amount	$ 711,589		$ 711,589
Accumulated amortization	(230,016)		(230,016)
Net carrying amount	481,573		481,573
Amortization expense associated with amortizable intangible assets (including deferred financing costs)	9,606	8,479	19,207	16,730
Customer Relationships and Acquisition Costs.
Amortizable intangible assets
Gross carrying amount	649,920		649,920
Accumulated amortization	(202,723)		(202,723)
Net carrying amount	447,197		447,197
Core Technology.
Amortizable intangible assets
Gross carrying amount	3,651		3,651
Accumulated amortization	(2,654)		(2,654)
Net carrying amount	997		997
Trademarks and Non-Compete Agreements
Amortizable intangible assets
Gross carrying amount	3,078		3,078
Accumulated amortization	(2,606)		(2,606)
Net carrying amount	472		472
Deferred Financing Costs
Amortizable intangible assets
Gross carrying amount	54,940		54,940
Accumulated amortization	(22,033)		(22,033)
Net carrying amount	$ 32,907		$ 32,907