Other Long-term Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Other Long-term Liabilities
Long-term derivative liabilities	$ 5,103	$ 12,401
Uncertain tax positions	1,224	1,224
Accrued interest on uncertain tax positions	70	50
Other long-term liabilities	466	492
Total	$ 6,863	$ 14,167