Stock-Based Compensation (Details 1) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding
Shares under options, Outstanding at January 1, 2012	1,011,089
Shares under options, Granted	164,500	176,250	325,000
Shares under options, Exercised	(9,168)
Shares under options, Outstanding at December 31, 2012	1,166,421	1,011,089
Shares under options, Exercisable at December 31, 2012	884,421
Shares under options, Vested or expected to vest at December 31, 2012	1,166,421
Weighted average exercise price, Outstanding at January 1, 2012	$ 27.24
Weighted average exercise price, Granted	$ 17.67	$ 25.18	$ 25.77
Weighted average exercise price, Exercised	$ 13.37
Weighted average exercise price, Outstanding at December 31, 2012	$ 26.00	$ 27.24
Weighted average exercise price, Exercisable at December 31, 2012	$ 27.65
Weighted average exercise price, Vested or expected to vest at December 31, 2012	$ 26.00
Remaining Contractual Life In Years, Outstanding at January 1, 2012	7 years 1 month 6 days	7 years 8 months 12 days
Remaining Contractual Life In Years, Outstanding at December 31, 2012	7 years 1 month 6 days	7 years 8 months 12 days
Remaining Contractual Life In Years, Exercisable at December 31, 2012	6 years 6 months
Remaining Contractual Life In Years, Vested or expected to vest at December 31, 2012	7 years 1 month 6 days
Intrinsic Value, Outstanding at January 1, 2012	$ 1,118
Intrinsic Value, Outstanding at December 31, 2012	1,178	1,118
Intrinsic Value, Exercisable at December 31, 2012	1,178
Intrinsic Value, Vested or expected to vest at December 31, 2012	$ 1,178