Stock-Based Compensation Plans (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2011 Y
Exercise Price Range One [Member]
Exercise Price Range [Abstract]
Exercise Price Range, Number of Outstanding Options	61,116
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 9.77
Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	6.29
Exercise Price Range, Number of Exercisable Options	34,844
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 9.60
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	5.68
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 0.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 10.00
Exercise Price Range Two [Member]
Exercise Price Range [Abstract]
Exercise Price Range, Number of Outstanding Options	4,754
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 15.75
Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	7.49
Exercise Price Range, Number of Exercisable Options	2,028
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 16.35
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	6.01
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 10.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 20.00
Exercise Price Range Three [Member]
Exercise Price Range [Abstract]
Exercise Price Range, Number of Outstanding Options	149,360
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 26.66
Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	6.74
Exercise Price Range, Number of Exercisable Options	55,500
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 25.82
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	2.76
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 20.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 30.00
Exercise Price Range Four [Member]
Exercise Price Range [Abstract]
Exercise Price Range, Number of Outstanding Options	52,305
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 39.16
Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	3.55
Exercise Price Range, Number of Exercisable Options	49,743
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 39.39
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	3.26
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 30.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 40.00
Exercise Price Range Five [Member]
Exercise Price Range [Abstract]
Exercise Price Range, Number of Outstanding Options	23,264
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 48.50
Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	4.37
Exercise Price Range, Number of Exercisable Options	23,264
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 48.50
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	4.37
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 40.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 50.00
Exercise Price Range Six [Member]
Exercise Price Range [Abstract]
Exercise Price Range, Number of Outstanding Options	14,781
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 51.40
Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	3.35
Exercise Price Range, Number of Exercisable Options	14,781
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 51.40
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	3.35
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 50.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 60.00
Exercise Price Range Seven [Member]
Exercise Price Range [Abstract]
Exercise Price Range, Number of Outstanding Options	3,219
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 66.60
Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	2.02
Exercise Price Range, Number of Exercisable Options	3,219
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 66.60
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	2.02
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 60.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 70.00
Exercise Price Range Eight [Member]
Exercise Price Range [Abstract]
Exercise Price Range, Number of Outstanding Options	12,808
Exercise Price Range, Outstanding Options, Weighted Average Exercise Price	$ 70.90
Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	2.14
Exercise Price Range, Number of Exercisable Options	12,808
Exercise Price Range, Exercisable Options, Weighted Average Exercise Price	$ 70.90
Exercise Price Range, Exercisable Options, Weighted Average Remaining Contractual Term	2.14
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 70.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 80.00