Summary of Significant Accounting Policies (Details 3) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Amortizable intangible assets
Gross carrying amount	$ 974,503
Accumulated amortization	(308,496)
Net carrying amount	666,007
Amortization expense associated with amortizable intangible assets (including deferred financing costs)	13,626	12,016
Customer Relationships and Acquisition Costs
Amortizable intangible assets
Gross carrying amount	907,801
Accumulated amortization	(288,191)
Net carrying amount	619,610
Core Technology
Amortizable intangible assets
Gross carrying amount	3,828
Accumulated amortization	(3,591)
Net carrying amount	237
Trademarks and Non-Compete Agreements
Amortizable intangible assets
Gross carrying amount	6,342
Accumulated amortization	(4,121)
Net carrying amount	2,221
Deferred Financing Costs
Amortizable intangible assets
Gross carrying amount	56,532
Accumulated amortization	(12,593)
Net carrying amount	$ 43,939