Derivative Financial Instruments Fair Value of the Company's Derivative Instruments (Details) - Designated as Hedging Instrument [Member] - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	$ 5,706	$ 1,530
Derivative Liability, Fair Value, Gross Liability	28,010	12,501
Interest rate swap agreements [Member] | Accrued expenses [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	27,992	846
Interest rate swap agreements [Member] | Other long-term liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	0	11,655
British pound forward contracts [Member] | Other assets, net [Member]
Derivatives, Fair Value [Line Items]
Derivative Asset, Fair Value, Gross Asset	5,706	1,530
British pound forward contracts [Member] | Other long-term liabilities [Member]
Derivatives, Fair Value [Line Items]
Derivative Liability, Fair Value, Gross Liability	$ 18	$ 0