Stock-Based Compensation (Summary Stock Option Activity, Options Outstanding and Options Exercisable) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Stock options, exercisable at December 31	3,482,068
Options Outstanding at December 31	4,741,732	4,769,122	5,649,233	7,396,537
Options Outstanding Weighted Average Exercise Price	$ 21.24
Options Outstanding Weighted Average Remaining Contractual Life (Years)	3.5
Aggregate Intrinsic Value	$ 60,505
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	2.4
Options Exercisable, Aggregate Intrinsic Value	$ 60,484
1.43 - 3.10 [Member]
Stock options, exercisable at December 31	1,727,398
Options Outstanding at December 31	1,727,398
Options Outstanding Weighted Average Exercise Price	$ 2.10
Options Outstanding Weighted Average Remaining Contractual Life (Years)	1.5
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	1.5
3.11 - 30.00 [Member]
Stock options, exercisable at December 31	856,544
Options Outstanding at December 31	862,650
Options Outstanding Weighted Average Exercise Price	$ 22.19
Options Outstanding Weighted Average Remaining Contractual Life (Years)	2.1
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	2.1
30.01 - 36.00 [Member]
Stock options, exercisable at December 31	490,190
Options Outstanding at December 31	606,133
Options Outstanding Weighted Average Exercise Price	$ 31.54
Options Outstanding Weighted Average Remaining Contractual Life (Years)	4.4
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	4.0
36.01 - 40.00 [Member]
Stock options, exercisable at December 31	153,086
Options Outstanding at December 31	1,130,705
Options Outstanding Weighted Average Exercise Price	$ 36.77
Options Outstanding Weighted Average Remaining Contractual Life (Years)	6.5
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	5.5
40.01 - 51.47 [Member]
Stock options, exercisable at December 31	254,850
Options Outstanding at December 31	414,846
Options Outstanding Weighted Average Exercise Price	$ 41.60
Options Outstanding Weighted Average Remaining Contractual Life (Years)	5.0
Options Exercisable, Weighted Average Remaining Contractual Life (Years)	4.8