Fair Value of Financial Instruments Financial Instruments Carried at Fair Value-Level 2 (Details) - Fair Value, Inputs, Level 2 [Member] - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets carried at fair value	$ 5,706	$ 1,530
Financial liabilities carried at fair value	28,010	12,501
Interest rate swap agreements [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial liabilities carried at fair value, Interest rate swap agreements	27,992	12,501
British pound forward contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Financial assets carried at fair value, British pound forward purchase contracts	5,706	1,530
Financial liabilities carried at fair value, British pound forward purchase contracts	$ 18	$ 0