Debt and interest Expense (Interest Expense Schedule) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Interest Expense [Abstract]
Contractual interest on Convertible Debentures	$ 10,156	$ 10,156
Amortization of debt discount on the Convertible Debentures	2,101	1,935
Interest capitalized to Property and equipment, net	(268)	(388)
Credit facility and other interest expense	607	637
Total interest expense	$ 12,596	$ 12,340