Share-Based Compensation (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options available for grant outstanding	0	0	0
Number of options available for grant expired in period	(2)	(7)	(26)
Number of options available for grant canceled in period	2	7	26
Number of options available for grant exercised in period	0	0	0
Options available for grant outstanding	0	0	0
Stock options outstanding	546	1,296	2,375
Options, expirations in period	(2)	(7)	(26)
Options, exercises in period	(260)	(743)	(1,053)
Stock options outstanding	284	546	1,296
Options outstanding, lower exercise price range (price per share)	$ 10.33	$ 10.33	$ 10.33	$ 6.44
Options outstanding, upper exercise price range (price per share)	$ 27.50	$ 27.50	$ 27.50	$ 27.50
Options outstanding, expired, price range lower limit ( price per share)	$ 11.81	$ 11.94	$ 6.44
Options outstanding, expired, price range upper limit (price per share)	$ 15.75	$ 16.80	$ 16.80
Options outstanding, exercised, price range lower limit (price per share)	$ 10.33	$ 10.33	$ 6.44
Options outstanding, exercised, price range upper limit (price per share)	$ 21.17	$ 27.50	$ 21.01