Share-Based Compensation and Capital Stock Summary of Change in Stock-Based Award Activity (Details) - $ / shares	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning balance (in shares)			2,193,502
Granted (in shares)	2,000	0	187,400	700,000
Exercised (in shares)	(99,971)	(104,442)	(257,167)	(297,398)
Expired (in shares)			(10,133)
Forfeited (in shares)			(30,300)
Outstanding, ending balance (in shares)	2,083,302	2,500,000	2,083,302	2,500,000
Options exercisable, ending balance (in shares)	1,376,077		1,376,077
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Beginning balance - weighted average exercise price (in dollars per share)			$ 48.26
Granted - Weighted average exercise price (in dollars per share)			60.64
Exercised - Weighted average exercise price (in dollars per share)			38.11
Expired - Weighted average exercise price (in dollars per share)			56.95
Forfeited - Weighted average exercise price (in dollars per share)			54.23
Ending balance - weighted average exercise price (in dollars per share)	$ 50.49		50.49
Options Exercisable, ending balance - Weighted average exercise price (in dollars per share)	$ 48.47		$ 48.47
Share-based Compensation Arrangement by Share-based Payment Award, Options, Weighted Average Remaining Contractual Term [Roll Forward]
Weighted Average Remaining Contractual Term - Outstanding, ending balance			4 years 3 months 18 days
Weighted Average Remaining Contractual Term - Options Exercisable, ending balance			3 years 10 months 25 days
Restricted stock
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Outstanding, beginning balance (in shares)			407,812
Restricted share grants (in shares)	21,562	21,357	167,142	188,509
Vested (in shares)			(177,050)
Forfeited (in shares)	(331)	(14,072)	(23,599)	(23,686)
Outstanding, ending balance (in shares)	374,305		374,305
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning balance - weighted average grant date fair value (in dollars per share)			$ 50.61
Granted - Weighted average grant date fair value (in dollars per share)	$ 62.34	$ 48.03	61.19	$ 51.21
Vested - Weighted average grant date fair value (in dollars per share)			49.99
Forfeited - Weighted average grant date fair value (in dollars per share)			54.68
Ending balance - weighted average grant date fair value (in dollars per share)	$ 55.37		$ 55.37
Performance Vested Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Outstanding, beginning balance (in shares)			235,980
Restricted share grants (in shares)	3,545	10,387	162,523	89,944
Performance-based leveraging (in shares)			9,491	22,056
Vested (in shares)		0	(38,329)	(22,062)
Forfeited (in shares)	(331)	(26,363)	(72,117)	(54,556)
Outstanding, ending balance (in shares)	297,548		297,548
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]
Beginning balance - weighted average grant date fair value (in dollars per share)			$ 47.59
Granted - Weighted average grant date fair value (in dollars per share)	$ 62.00	$ 48.14	60.63	$ 47.85
Performance-Based Leveraging - Weighted average grant date fair value (in dollars per share)			45.59
Vested - Weighted average grant date fair value (in dollars per share)			46.19
Forfeited - Weighted average grant date fair value (in dollars per share)			38.89
Ending balance - weighted average grant date fair value (in dollars per share)	$ 56.95		$ 56.95
Tranche Two | Performance Vested Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Performance-based leveraging (in shares)			9,491
Vested (in shares)	0		(38,329)