Long-Term Obligations (Interest Expense Recognized) (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Amortization of discount on convertible debentures			$ 14,745	$ 13,750
2.75% Series A [Member]
Contractual coupon interest	1,891	1,891	5,672	5,672
Amortization of discount on convertible debentures	2,575	2,405	7,595	7,095
Interest expense	4,466	4,296	13,267	12,767
2.75% Series B [Member]
Contractual coupon interest	1,891	1,891	5,672	5,672
Amortization of discount on convertible debentures	2,426	2,259	7,150	6,655
Interest expense	$ 4,317	$ 4,150	$ 12,822	$ 12,327