Stock-Based Compensation (Additional Information on Options) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Closing stock price used to calculate intrinsic value	$ 63.05
Share Based Compensation Arrangement by Share Based Payment Award, Expiration Date	10 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	4 years
Range One [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices	$8.57 - $14.70
Range of Exercise Prices, Lower Limit	$ 8.57
Range of Exercise Prices, Upper Limit	$ 14.70
Options Outstanding, Number of Options	178,435
Options Outstanding, Weighted Average Remaining Contractual Term (years)	1.07
Options Outstanding, Weighted Average Exercise Price	$ 8.63
Options Outstanding, Aggregate Intrinsic Value	$ 9,710
Options Exercisable, Exercisable Shares	178,435
Options Exercisable, Weighted Average Remaining Contractual Life (years)	1.07
Options Exercisable, Weighted Average Exercise Price	$ 8.63
Options Exercisable, Aggregate Intrinsic Value	9,710
Range Two [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices	$19.88 - $45.31
Range of Exercise Prices, Lower Limit	$ 19.88
Range of Exercise Prices, Upper Limit	$ 45.31
Options Outstanding, Number of Options	691,680
Options Outstanding, Weighted Average Remaining Contractual Term (years)	2.92
Options Outstanding, Weighted Average Exercise Price	$ 22.76
Options Outstanding, Aggregate Intrinsic Value	27,867
Options Exercisable, Exercisable Shares	691,680
Options Exercisable, Weighted Average Remaining Contractual Life (years)	2.92
Options Exercisable, Weighted Average Exercise Price	$ 22.76
Options Exercisable, Aggregate Intrinsic Value	27,867
Range Three [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices	$57.28 - $59.35
Range of Exercise Prices, Lower Limit	$ 57.28
Range of Exercise Prices, Upper Limit	$ 59.35
Options Outstanding, Number of Options	92,201
Options Outstanding, Weighted Average Remaining Contractual Term (years)	9.29
Options Outstanding, Weighted Average Exercise Price	$ 57.42
Options Outstanding, Aggregate Intrinsic Value	519
Options Exercisable, Exercisable Shares	0
Options Exercisable, Weighted Average Remaining Contractual Life (years)	0.00
Options Exercisable, Weighted Average Exercise Price	$ 0.00
Options Exercisable, Aggregate Intrinsic Value	0
Range Four [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices	$8.57 - $59.35
Range of Exercise Prices, Lower Limit	$ 8.57
Range of Exercise Prices, Upper Limit	$ 59.35
Options Outstanding, Number of Options	962,316
Options Outstanding, Weighted Average Remaining Contractual Term (years)
Options Outstanding, Weighted Average Exercise Price
Options Outstanding, Aggregate Intrinsic Value	38,096
Options Exercisable, Exercisable Shares	870,115
Options Exercisable, Weighted Average Remaining Contractual Life (years)
Options Exercisable, Weighted Average Exercise Price
Options Exercisable, Aggregate Intrinsic Value	37,577
Vested or Expected to Vest [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Range of Exercise Prices, Lower Limit	$ 8.57
Range of Exercise Prices, Upper Limit	$ 59.35
Vested or Expected to Vest, Range of Exercise Prices	$8.57 - $59.35
Vested or Expected to Vest, Number of Options	962,316
Vested or Expected to Vest, Weighted Average Remaining Contractual Life (years)	3.19
Vested or Expected to Vest, Weighted Average Exercise Price	$ 23.46
Vested or Expected to Vest, Aggregate Intrinsic Value	$ 38,096