Fair Value Measurements (Details) (USD $) In Thousands	Sep. 30, 2011	Dec. 31, 2010
Derivative Liabilities	$ (2,965)	$ (667)
3.375% Convertible Notes [Member]
Convertible Debt, Fair Value Disclosure	55,835	57,244
Convertible Debt Par Value	55,636	55,636
Quoted Prices in Active Markets for Identical Assets (Level 1)
Derivative Assets	0	0
Derivative Liabilities	0	0
Rabbi Trust Asset Fair Value Disclosure	1,356	1,350
Financial Instruments Asset Liabilities at Fair Value Net	1,356	1,350
Significant Other Observable Inputs (Level 2)
Derivative Assets	0	1,617
Derivative Liabilities	(2,965)	(667)
Rabbi Trust Asset Fair Value Disclosure	0	0
Financial Instruments Asset Liabilities at Fair Value Net	(2,965)	950
Significant Unobservable Inputs (Level 3)
Derivative Assets	0	0
Derivative Liabilities	0	0
Rabbi Trust Asset Fair Value Disclosure	0	0
Financial Instruments Asset Liabilities at Fair Value Net	0	0
Estimate of Fair Value, Fair Value Disclosure [Member]
Derivative Assets	0	1,617
Derivative Liabilities	(2,965)	(667)
Rabbi Trust Asset Fair Value Disclosure	1,356	1,350
Financial Instruments Asset Liabilities at Fair Value Net	$ (1,609)	$ 2,300