Derivative Financial Instruments Fair Value of Derivative Instrument (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Interest rate swap [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Financial assets carried at fair value	$ 136	$ 36,987
Financial liabilities carried at fair value	4,711	2,439
Interest rate swap [Member] | Designated as Hedging Instrument [Member] | Prepaid expenses and other [Member]
Derivatives, Fair Value [Line Items]
Financial assets carried at fair value	35	0
Interest rate swap [Member] | Designated as Hedging Instrument [Member] | Other assets, net [Member]
Derivatives, Fair Value [Line Items]
Financial assets carried at fair value	101	36,987
Interest rate swap [Member] | Designated as Hedging Instrument [Member] | Accrued expenses [Member]
Derivatives, Fair Value [Line Items]
Financial liabilities carried at fair value	2,249	1,601
Interest rate swap [Member] | Designated as Hedging Instrument [Member] | Other long-term liabilities [Member]
Derivatives, Fair Value [Line Items]
Financial liabilities carried at fair value	2,462	838
Cross-currency swap agreement [Member] | Not Designated as Hedging Instrument [Member] | Prepaid expenses and other [Member]
Derivatives, Fair Value [Line Items]
Financial assets carried at fair value	$ 0	$ 16,056