Share-Based Compensation and Capital Stock - Range Of Exercise Prices (Details)	12 Months Ended
	Dec. 31, 2018 $ / shares shares
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options Outstanding, Number Outstanding (in shares) | shares	1,186,180
Options Outstanding, Weighted Average Remaining Contractual Life	3 years 6 months
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 54.13
Options Exercisable, Number Exercisable (in shares) | shares	753,681
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 49.55
Range 1
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	34.13
Exercise price range, upper range limit (in dollars per share)	$ 39.00
Options Outstanding, Number Outstanding (in shares) | shares	52,664
Options Outstanding, Weighted Average Remaining Contractual Life	1 year 1 month 10 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 36.76
Options Exercisable, Number Exercisable (in shares) | shares	52,664
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 36.76
Range 2
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	39.01
Exercise price range, upper range limit (in dollars per share)	$ 48.75
Options Outstanding, Number Outstanding (in shares) | shares	417,591
Options Outstanding, Weighted Average Remaining Contractual Life	2 years 2 months 27 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 45.59
Options Exercisable, Number Exercisable (in shares) | shares	417,591
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 45.59
Range 3
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	48.76
Exercise price range, upper range limit (in dollars per share)	$ 65.00
Options Outstanding, Number Outstanding (in shares) | shares	610,415
Options Outstanding, Weighted Average Remaining Contractual Life	4 years
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 56.73
Options Exercisable, Number Exercisable (in shares) | shares	283,426
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 57.77
Range 4
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price range, lower range limit (in dollars per share)	65.01
Exercise price range, upper range limit (in dollars per share)	$ 81.55
Options Outstanding, Number Outstanding (in shares) | shares	105,510
Options Outstanding, Weighted Average Remaining Contractual Life	6 years 2 months 15 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 81.55
Options Exercisable, Number Exercisable (in shares) | shares	0
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 0.00