Summary of Significant Accounting Policies (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Amortizable intangible assets
Gross carrying amount	$ 776,528		$ 776,528
Accumulated amortization	(275,145)		(275,145)
Net carrying amount	501,383		501,383
Amortization expense associated with amortizable intangible assets (including deferred financing costs)	10,973	9,606	22,989	19,207
Customer Relationships and Acquisition Costs.
Amortizable intangible assets
Gross carrying amount	702,857		702,857
Accumulated amortization	(245,147)		(245,147)
Net carrying amount	457,710		457,710
Core Technology.
Amortizable intangible assets
Gross carrying amount	3,707		3,707
Accumulated amortization	(3,317)		(3,317)
Net carrying amount	390		390
Trademarks and Non-Compete Agreements
Amortizable intangible assets
Gross carrying amount	5,824		5,824
Accumulated amortization	(3,464)		(3,464)
Net carrying amount	2,360		2,360
Deferred Financing Costs
Amortizable intangible assets
Gross carrying amount	64,140		64,140
Accumulated amortization	(23,217)		(23,217)
Net carrying amount	$ 40,923		$ 40,923