Debt (Details 3) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Interest expense excluding amortization of debt issue costs
Interest expense	$ 3,003	$ 2,867	$ 8,904	$ 8,505
Conversion value in excess of principal amount (in thousands)			$ 105,655
Derivative transactions entered into in connection with the convertible notes			None
Senior Subordinated Notes [Member]
Interest expense excluding amortization of debt issue costs
Remaining period over which discount will be amortized	9		9
Conversion price	$ 31.75		$ 31.75
Number of shares to be delivered upon conversion			2,074,918