Debt (Schedule Of Interest Expense, Net) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Debt [Abstract]
Contractual interest payments and other interest expense	$ 27,500,000	$ 27,000,000	$ 23,800,000
Senior convertible note discount and related investor fee accretion	4,200,000
Amortization of deferred financing costs	3,300,000	3,300,000	2,100,000
Total interest expense	35,000,000	30,300,000	25,900,000
Interest income	(600,000)	(1,200,000)	(1,200,000)
Interest expense, net	$ (34,423,000)	$ (29,105,000)	$ (24,690,000)