Stock-based Compensation Stock-based Compensation (Details 4) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Stock Option Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value per share	$ 7.32	$ 5.86	$ 7.32	$ 5.86
Total fair value awards granted	$ 4,446	$ 5,817	$ 4,446	$ 5,817
Total fair value of awards vested	4,651	5,013	4,662	5,026
Total intrinsic value of options exercised	12,418	652	21,334	1,839
Restricted Stock Unit Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value per share	$ 32.87	$ 23.43	$ 32.85	$ 23.38
Total fair value of awards granted	21,660	25,188	21,830	25,330
Total fair value of awards vested	24,157	13,134	27,761	13,319
Employee Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average grant date fair value per share	$ 7.87	$ 5.25	$ 7.87	$ 5.25
Total fair value of shares expected to be issued	$ 591	$ 552	$ 591	$ 552