Common Stock (Schedule of Stock Option Activity) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at beginning of period	1,288	1,536	3,353
Granted	74	1,148	63
Exercised	(484)	(1,362)	(1,831)
Canceled	(3)	(34)	(49)
Outstanding at end of period	875	1,288	1,536
Exercisable	684	770	674
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding at beginning of period	$ 13.69	$ 9.30	$ 14.30
Granted	$ 53.78	$ 22.17	$ 31.49
Exercised	$ 12.22	$ 15.42	$ 19.25
Canceled	$ 23.63	$ 32.26	$ 7.85
Outstanding at end of period	$ 17.85	$ 13.69	$ 9.30
Exercisable	$ 11.67	$ 10.97	$ 10.14