Share-Based Compensation (Details 4) (USD $) In Thousands, except Per Share data, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average exercise price of outstanding options (price per share)	$ 14.62	$ 15.91
Approved by Stockholders [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of securities to be issued upon exercise of outstanding options or vesting of restricted stock units ( securitites)	1,508
Weighted-average exercise price of outstanding options (price per share)	$ 15.03
Number of securities remaining availablefor future issuance under equity compensation plans (securitites)	3,047
1996 Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of securities to be issued upon exercise of outstanding options or vesting of restricted stock units ( securitites)	223
Weighted-average exercise price of outstanding options (price per share)	$ 14.76
Number of securities remaining availablefor future issuance under equity compensation plans (securitites)	0
1996 Directors Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of securities to be issued upon exercise of outstanding options or vesting of restricted stock units ( securitites)	36
Weighted-average exercise price of outstanding options (price per share)	$ 16.75
Number of securities remaining availablefor future issuance under equity compensation plans (securitites)	0
2005 Performance Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of securities to be issued upon exercise of outstanding options or vesting of restricted stock units ( securitites)	176
Number of securities remaining availablefor future issuance under equity compensation plans (securitites)	1,974
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of securities to be issued upon exercise of outstanding options or vesting of restricted stock units ( securitites)	1,073
Number of securities remaining availablefor future issuance under equity compensation plans (securitites)	1,073
Not Approved by Stockholders [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of securities to be issued upon exercise of outstanding options or vesting of restricted stock units ( securitites)	1,577
Weighted-average exercise price of outstanding options (price per share)	$ 10.33
Number of securities remaining availablefor future issuance under equity compensation plans (securitites)	3,047
1998 Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of securities to be issued upon exercise of outstanding options or vesting of restricted stock units ( securitites)	25
Weighted-average exercise price of outstanding options (price per share)	$ 10.33
Number of securities remaining availablefor future issuance under equity compensation plans (securitites)	0
Non-Plan Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of securities to be issued upon exercise of outstanding options or vesting of restricted stock units ( securitites)	44
Number of securities remaining availablefor future issuance under equity compensation plans (securitites)	0