Derivative Instruments, Hedging Activities and Fair Value (Details 5) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Unit Adjustment Liability
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 93,762		$ 106,343
Payments	(5,580)		(5,580)
Change in fair value to the unit adjustment liability	2,245	[1]	2,546	[1]
Balance at end of period	90,427		103,308	[2]
Fair value measurements recurring | Level 2
Assets
Foreign currency forward exchange contracts	6,381				4,485
Cross-currency interest rate swaps	90,541				52,989
Liabilities
Foreign currency forward exchange contracts	3,334				4,618
Cross-currency interest rate swaps	$ 17				$ 2,599

[1] See Note 6, Equity Method Investments, for additional information related to the unit adjustment liability.

[2] Does not total due to rounding.