Fair Value Measurements (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Fair value assets and liabilities measured on recurring basis:
Marketable equity securities	$ 22,769	$ 17,053
Fair value on a recurring basis | Fair Value
Fair value assets and liabilities measured on recurring basis:
Marketable equity securities	22,769
Total fair value assets and liabilities measured on recurring basis	8,423
Fair value on a recurring basis | Fair Value | Interest-rate swap contracts
Fair value assets and liabilities measured on recurring basis:
Derivative liabilities	(13,319)
Fair value on a recurring basis | Fair Value | Currency swap liabilities
Fair value assets and liabilities measured on recurring basis:
Derivative liabilities	(2,317)
Fair value on a recurring basis | Fair Value | Warrants
Fair value assets and liabilities measured on recurring basis:
Derivative assets	1,290
Fair value on a recurring basis | Level 1
Fair value assets and liabilities measured on recurring basis:
Marketable equity securities	22,769
Total fair value assets and liabilities measured on recurring basis	22,769
Fair value on a recurring basis | Level 2
Fair value assets and liabilities measured on recurring basis:
Total fair value assets and liabilities measured on recurring basis	(15,636)
Fair value on a recurring basis | Level 2 | Interest-rate swap contracts
Fair value assets and liabilities measured on recurring basis:
Derivative liabilities	(13,319)
Fair value on a recurring basis | Level 2 | Currency swap liabilities
Fair value assets and liabilities measured on recurring basis:
Derivative liabilities	(2,317)
Fair value on a recurring basis | Level 3
Fair value assets and liabilities measured on recurring basis:
Total fair value assets and liabilities measured on recurring basis	1,290
Fair value on a recurring basis | Level 3 | Warrants
Fair value assets and liabilities measured on recurring basis:
Derivative assets	$ 1,290