Stock-based Compensation Stock-based Compensation (Details 4) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Stock Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total fair value of awards vested	$ 13	$ 15
Total intrinsic value of options exercised	1,187	1,420
Restricted Stock Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value per share	$ 17.30	$ 24.10
Total fair value of awards granted	142	51
Total fair value of awards vested	$ 184	$ 340