Bank Credit Agreements and Other Short-Term and Long-Term Debt (Interest expense) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Debt Instruments [Abstract]
Notes Contractual Interest Expense	$ 2,267	$ 3,077	$ 3,576
Amortization of discount on convertible senior notes	6,032	7,656	8,302
Amortization Of Debt Issuance Cost	412	549	648
Total	$ 8,711	$ 11,282	$ 12,526