Share-Based Compensation and Capital Stock Summary of Change in Stock-Based Award Activity (Details) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015		Jun. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding, beginning balance - Shares			1,903,177
Granted - Shares	0	0	498,911		700,000
Exercised - Shares	(3,829)	0	(232,792)		(58,749)
Expired - Shares			0
Forfeited - Shares			(5,569)
Outstanding, ending balance - Shares	2,163,727	2,300,000	2,163,727		2,300,000
Options exercisable, ending balance - Shares	1,053,447		1,053,447
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Outstanding, beginning balance - Weighted average exercise price (in dollars per share)			$ 33.03
Granted - Weighted average exercise price (in dollars per share)			63.47
Exercised - Weighted average exercise price (in dollars per share)			24.47
Expired - Weighted average exercise price (in dollars per share)			0.00
Forfeited - Weighted average exercise price (in dollars per share)			51.64
Outstanding, ending balance - Weighted average exercise price (in dollars per share)	$ 40.92		40.92
Options Exercisable, ending balance - Weighted average exercise price (in dollars per share)	$ 29.11		$ 29.11
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 4 months 10 days
Weighted Average Remaining Contractual Term - Options Exercisable, ending balance			2 years 7 months 27 days
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Outstanding, beginning balance - Shares			479,556
Granted - shares	20,653	17,262	106,445		147,055
Vested - Shares			(189,592)
Forfeited - Shares	(3,664)	(2,964)	(8,442)		(4,296)
Outstanding, ending balance - Shares	387,967		387,967
Outstanding, beginning balance - Weighted average grant date fair value (in dollars per share)			$ 40.14
Granted - Weighted average grant date fair value (in dollars per share)	$ 62.57	$ 44.62	63.29		$ 46.46
Vested - Weighted average grant date fair value (in dollars per share)			39.15
Forfeited - Weighted average grant date fair value (in dollars per share)			44.72
Outstanding, ending balance - Weighted average grant date fair value (in dollars per share)	$ 46.88		$ 46.88
Performance Vested Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Outstanding, beginning balance - Shares			200,286
Granted - shares	20,956	0	51,309		24,678
Performance-based leveraging - Shares			3,850	[1]	10,251
Vested - Shares	0	0	(42,326)		(28,886)
Forfeited - Shares	0	0	0		0
Outstanding, ending balance - Shares	213,119		213,119
Outstanding, beginning balance - Weighted average grant date fair value (in dollars per share)			$ 38.28
Granted - Weighted average grant date fair value (in dollars per share)	$ 57.27		60.94		$ 45.59
Performance-Based Leveraging - Weighted average grant date fair value (in dollars per share)			35.60
Vested - Weighted average grant date fair value (in dollars per share)			35.60
Forfeited - Weighted average grant date fair value (in dollars per share)			0.00
Outstanding, ending balance - Weighted average grant date fair value (in dollars per share)	$ 44.22		$ 44.22

[1] PVRSU units outstanding have been increased by 3,850 units due to the Company exceeding the targeted performance conditions contained in PVRSUs granted in prior periods during the six months ended June 30, 2015.