Stock-Based Compensation (Shares Authorized Under Stock Option Plans By Exercise Price Range) (Details) (USD $)	12 Months Ended
	Dec. 31, 2011 years
$19.04 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices Minimum	$ 19.04
Outstanding and Exercisable Options, Number Of Shares	16,400
Outstanding and Exercisable Options, Weighted Average Remaining Contractual Life, years	1.0
Outstanding and Exercisable Options, Weighted Average Exercise Price	$ 19.04
$21.50 - $22.95 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices Minimum	$ 21.50
Exercise Prices Maximum	$ 22.95
Outstanding and Exercisable Options, Number Of Shares	38,810
Outstanding and Exercisable Options, Weighted Average Remaining Contractual Life, years	1.9
Outstanding and Exercisable Options, Weighted Average Exercise Price	$ 22.76
$37.69 - $37.83 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices Minimum	$ 37.69
Exercise Prices Maximum	$ 37.83
Outstanding and Exercisable Options, Number Of Shares	83,770
Outstanding and Exercisable Options, Weighted Average Remaining Contractual Life, years	3.0
Outstanding and Exercisable Options, Weighted Average Exercise Price	$ 37.80
$20.10 - $20.46 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices Minimum	$ 20.10
Exercise Prices Maximum	$ 20.46
Outstanding and Exercisable Options, Number Of Shares	14,000
Outstanding and Exercisable Options, Weighted Average Remaining Contractual Life, years	1.1
Outstanding and Exercisable Options, Weighted Average Exercise Price	$ 20.37
$28.23 - $41.21 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices Minimum	$ 28.23
Exercise Prices Maximum	$ 41.21
Outstanding and Exercisable Options, Number Of Shares	80,500
Outstanding and Exercisable Options, Weighted Average Remaining Contractual Life, years	6.4
Outstanding and Exercisable Options, Weighted Average Exercise Price	$ 36.45
$53.81 - $73.26 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise Prices Minimum	$ 53.81
Exercise Prices Maximum	$ 73.26
Outstanding and Exercisable Options, Number Of Shares	105,000
Outstanding and Exercisable Options, Weighted Average Remaining Contractual Life, years	6.5
Outstanding and Exercisable Options, Weighted Average Exercise Price	$ 61.24