Long-Term Debt (Details 1) (2.0% Convertible Senior Notes due May 15, 2012 [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
2.0% Convertible Senior Notes due May 15, 2012 [Member]
Interest expense:
Non-cash interest	$ 11,361	$ 10,646	$ 9,974
Cash interest	5,199	5,200	5,200
Total interest expense	$ 16,560	$ 15,846	$ 15,174