Share-Based Compensation Plan (Stock Options Outstanding Per Range of Exercise Prices) (Details) (Stock Options [Member], USD $)	12 Months Ended
	Dec. 31, 2012
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	997,222
Options Outstanding, Weighted Average Exercise Price Per Share	$ 27.24
Options Outstanding, Weighted Average Contractual Term	5 years 6 months 29 days
Options Exercisable, Number Exercisable	682,457
Options Exercisable, Weighted Average Exercise Price Per Share	$ 29.19
Options Exercisable, Weighted Average Contractual Term	4 years 0 months 22 days
Minimum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price per share, lower price range limit	$ 19.43
Maximum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price per share, upper price range limit	$ 39.69
Range of Exercise Prices Per Share, $19.43 - 21.10 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	166,779
Options Outstanding, Weighted Average Exercise Price Per Share	$ 20.43
Options Outstanding, Weighted Average Contractual Term	7 years 5 months 20 days
Options Exercisable, Number Exercisable	101,288
Options Exercisable, Weighted Average Exercise Price Per Share	$ 20.74
Options Exercisable, Weighted Average Contractual Term	6 years 11 months 5 days
Range of Exercise Prices Per Share, $19.43 - 21.10 [Member] | Minimum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price per share, lower price range limit	$ 19.43
Range of Exercise Prices Per Share, $19.43 - 21.10 [Member] | Maximum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price per share, upper price range limit	$ 21.10
Range of Exercise Prices Per Share, $13.78 - 24.86 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	521,311
Options Outstanding, Weighted Average Exercise Price Per Share	$ 24.28
Options Outstanding, Weighted Average Contractual Term	6 years 11 months 15 days
Options Exercisable, Number Exercisable	272,037
Options Exercisable, Weighted Average Exercise Price Per Share	$ 24.69
Options Exercisable, Weighted Average Contractual Term	5 years 0 months 25 days
Range of Exercise Prices Per Share, $13.78 - 24.86 [Member] | Minimum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price per share, lower price range limit	$ 23.78
Range of Exercise Prices Per Share, $13.78 - 24.86 [Member] | Maximum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price per share, upper price range limit	$ 24.86
Range of Exercise Prices Per Share, $32.28 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	131,000
Options Outstanding, Weighted Average Exercise Price Per Share	$ 32.28
Options Outstanding, Weighted Average Contractual Term	2 years 11 months 19 days
Options Exercisable, Number Exercisable	131,000
Options Exercisable, Weighted Average Exercise Price Per Share	$ 32.28
Options Exercisable, Weighted Average Contractual Term	2 years 11 months 19 days
Range of Exercise Prices Per Share, $32.28 [Member] | Maximum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price per share, upper price range limit	$ 32.28
Range of Exercise Prices Per Share, $35.67 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	48,720
Options Outstanding, Weighted Average Exercise Price Per Share	$ 35.67
Options Outstanding, Weighted Average Contractual Term	0 years 11 months 12 days
Options Exercisable, Number Exercisable	48,720
Options Exercisable, Weighted Average Exercise Price Per Share	$ 35.67
Options Exercisable, Weighted Average Contractual Term	0 years 11 months 12 days
Range of Exercise Prices Per Share, $35.67 [Member] | Maximum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price per share, upper price range limit	$ 35.67
Range of Exercise Prices Per Share, $39.69 [Member] [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding	129,412
Options Outstanding, Weighted Average Exercise Price Per Share	$ 39.69
Options Outstanding, Weighted Average Contractual Term	1 year 11 months 12 days
Options Exercisable, Number Exercisable	129,412
Options Exercisable, Weighted Average Exercise Price Per Share	$ 39.69
Options Exercisable, Weighted Average Contractual Term	1 year 11 months 12 days
Range of Exercise Prices Per Share, $39.69 [Member] [Member] | Maximum [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price per share, upper price range limit	$ 39.69