Debt and Commitments (Details 3) (Convertible Debt [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Debt Instrument [Line Items]
Debt Instrument, Convertible, Interest Expense	$ 5,261	$ 11,075	$ 12,159
Coupon [Member] | 3.75% Convertible Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Interest Expense	1,225	3,469	3,610
Coupon [Member] | 3.375% Convertible Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Interest Expense	1,878	1,878	2,629
Debt discount amortization [Member] | 3.75% Convertible Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Interest Expense	114	3,841	3,685
Debt discount amortization [Member] | 3.375% Convertible Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Interest Expense	$ 2,044	$ 1,887	$ 2,235