Common Stock (Schedule of Stock Option Exercise Prices) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified					12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2013 $0.01-5.00 [Member]	Dec. 31, 2013 5.01-10.00 [Member]	Dec. 31, 2013 10.01-15.00 [Member]	Dec. 31, 2013 15.01-20.00 [Member]	Dec. 31, 2013 20.01-25.00 [Member]	Dec. 31, 2013 25.01-30.00 [Member]	Dec. 31, 2013 30.01-35.00 [Member]	Dec. 31, 2013 35.01-40.00 [Member]	Dec. 31, 2013 40.01-45.00 [Member]	Dec. 31, 2013 45.01-50.00 [Member]	Dec. 31, 2013 50.01-55.00 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Minimum					$ 0.01	$ 5.01	$ 10.01	$ 15.01	$ 20.01	$ 25.01	$ 30.01	$ 35.01	$ 40.01	$ 45.01	$ 50.01
Range of Exercise Prices, Maximum					$ 5.00	$ 10.00	$ 15.00	$ 20.00	$ 25.00	$ 30.00	$ 35.00	$ 40.00	$ 45.00	$ 50.00	$ 55.00
Amount Outstanding	875	1,288	1,536	3,353	243	209	40	69	10	107	72	0	51	0	74
Weighted Average Remaining Contractual Life					5 years 2 months	6 years 2 months	5 years 1 month	4 years 2 months	2 years 11 months	6 years 0 months	7 years 0 months	0 years	8 years 1 month	0 years	9 years 2 months
Weighted Average Exercise Price	$ 17.85	$ 13.69	$ 9.30	$ 14.30	$ 3.38	$ 8.32	$ 14.43	$ 16.21	$ 24.67	$ 25.81	$ 31.77	$ 0.00	$ 41.25	$ 0.00	$ 53.78
Amount Exercisable	684	770	674		243	209	37	68	10	55	45	0	17	0	0
Weighted Average Exercise Price	$ 11.67	$ 10.97	$ 10.14		$ 3.38	$ 8.32	$ 14.48	$ 16.22	$ 24.67	$ 25.96	$ 31.72	$ 0.00	$ 41.25	$ 0.00	$ 0.00