Debt and Commitments (Details 3) (Convertible Debt [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Debt Instrument [Line Items]
Debt Instrument, Convertible, Interest Expense	$ 4,089	$ 5,261	$ 11,075
Coupon [Member] | 3.375% Convertible Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Interest Expense	1,878	1,878	1,878
Coupon [Member] | 3.75% Convertible Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Interest Expense	0	1,225	3,469
Debt discount amortization [Member] | 3.375% Convertible Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Interest Expense	2,211	2,044	1,887
Debt discount amortization [Member] | 3.75% Convertible Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Convertible, Interest Expense	$ 0	$ 114	$ 3,841