Stock-Based Compensation Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range (Details) - Employee Stock Option [Member] $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($) $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding options | shares	2,395,107
Outstanding options, weighted average remaining contractual life (in years)	6 years
Outstanding options, weighted average exercise price (in dollars per share)	$ 24.13
Exercisable options | shares	1,389,060
Exercisable options, weighted average exercise price (in dollars per share)	$ 23.71
Unrecognized Compensation Cost (in Milliions) | $	$ 13.6
Weighted Average Period Of Recognition For Unrecognized Compensation Costs	3 years 4 days
Range 1 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	$ 9.66
Exercise price upper range limit	$ 15.65
Outstanding options | shares	307,564.0000
Outstanding options, weighted average remaining contractual life (in years)	3 years 4 months 13 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 12.78
Exercisable options | shares	235,424.0000
Exercisable options, weighted average exercise price (in dollars per share)	$ 12.40
Range 2 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	16.01
Exercise price upper range limit	$ 18.92
Outstanding options | shares	271,050.0000
Outstanding options, weighted average remaining contractual life (in years)	7 years 3 months
Outstanding options, weighted average exercise price (in dollars per share)	$ 17.75
Exercisable options | shares	125,835.0000
Exercisable options, weighted average exercise price (in dollars per share)	$ 18.06
Range 3 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	19.79
Exercise price upper range limit	$ 27.75
Outstanding options | shares	266,699.0000
Outstanding options, weighted average remaining contractual life (in years)	5 years 3 months 15 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 20.70
Exercisable options | shares	161,529.0000
Exercisable options, weighted average exercise price (in dollars per share)	$ 20.60
Range 4 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	28.92
Exercise price upper range limit	$ 30.12
Outstanding options | shares	270,941.0000
Outstanding options, weighted average remaining contractual life (in years)	6 years 5 months 5 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 23.14
Exercisable options | shares	140,896.0000
Exercisable options, weighted average exercise price (in dollars per share)	$ 23.07
Range 5 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	30.91
Exercise price upper range limit	$ 31.91
Outstanding options | shares	401,668.0000
Outstanding options, weighted average remaining contractual life (in years)	6 years 10 months 28 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 26.71
Exercisable options | shares	224,248.0000
Exercisable options, weighted average exercise price (in dollars per share)	$ 26.83
Range 6 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price lower range limit	31.94
Exercise price upper range limit	$ 39.92
Outstanding options | shares	289,586.0000
Outstanding options, weighted average remaining contractual life (in years)	6 years 4 months 17 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 29.11
Exercisable options | shares	184,310.9091
Exercisable options, weighted average exercise price (in dollars per share)	$ 29.20
Range 7 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding options | shares	359,211.0000
Outstanding options, weighted average remaining contractual life (in years)	5 years 11 months 27 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 30.48
Exercisable options | shares	192,742.9091
Exercisable options, weighted average exercise price (in dollars per share)	$ 30.52
Range 8 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding options | shares	211,168.0000
Outstanding options, weighted average remaining contractual life (in years)	6 years 3 months 22 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 31.24
Exercisable options | shares	109,613.9091
Exercisable options, weighted average exercise price (in dollars per share)	$ 31.24
Range 9 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding options | shares	15,000.0000
Outstanding options, weighted average remaining contractual life (in years)	6 years 5 months 16 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 31.91
Exercisable options | shares	12,600.0000
Exercisable options, weighted average exercise price (in dollars per share)	$ 31.91
Range 10 [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Outstanding options | shares	2,220.0000
Outstanding options, weighted average remaining contractual life (in years)	6 years 3 months 29 days
Outstanding options, weighted average exercise price (in dollars per share)	$ 31.94
Exercisable options | shares	1,860.0000
Exercisable options, weighted average exercise price (in dollars per share)	$ 31.94