Fair Value Measurements (Details) (Fair value on a recurring basis, USD $) In Thousands, unless otherwise specified	Dec. 31, 2013
Fair Value
Fair value assets and liabilities measured on recurring basis:
Total fair value assets and liabilities measured on recurring basis	$ (8,701)
Fair Value | Interest-rate swap contracts
Fair value assets and liabilities measured on recurring basis:
Derivative assets	2,325
Derivative liabilities	(8,384)
Fair Value | Currency swap contracts
Fair value assets and liabilities measured on recurring basis:
Derivative liabilities	(2,756)
Fair Value | Warrants
Fair value assets and liabilities measured on recurring basis:
Derivative assets	114
Level 2
Fair value assets and liabilities measured on recurring basis:
Total fair value assets and liabilities measured on recurring basis	(8,815)
Level 2 | Interest-rate swap contracts
Fair value assets and liabilities measured on recurring basis:
Derivative assets	2,325
Derivative liabilities	(8,384)
Level 2 | Currency swap contracts
Fair value assets and liabilities measured on recurring basis:
Derivative liabilities	(2,756)
Level 3
Fair value assets and liabilities measured on recurring basis:
Total fair value assets and liabilities measured on recurring basis	114
Level 3 | Warrants
Fair value assets and liabilities measured on recurring basis:
Derivative assets	$ 114