Share-Based Compensation and Capital Stock Narrative (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013		Jan. 01, 2014
Share-Based Compensation and Capital Stock [Line Items]
Stock options granted, shares	0	0	651,757		200,000
Stock options granted, fair value			$ 5,700,000		$ 1,700,000
Aggregate intrinsic value of stock options, outstanding	41,400,000		41,400,000
Aggregate intrinsic value of stock options, exercisable	32,100,000		32,100,000
Total intrinsic value of options exercised	3,100,000	500,000	4,400,000		3,400,000
Proceeds from exercise of stock options	3,400,000	700,000	4,984,000		6,677,000
Stock options exercised	131,808	29,008	190,557		263,073
Frequency of dividend payments			quarterly
Cash dividends declared per share (in dollars per share)	$ 0.185	$ 0.185	$ 0.555		$ 0.555
Dividends paid			32,767,000		22,026,000
Common stock purchased under stock repurchase program, shares	400,000		400,000
Stock Repurchased During Period, Value	18,400,000		18,400,000
Shares paid for tax withholding for share based compensation	15,834		110,579
Payments related to tax withholding for share-based compensation	800,000		5,300,000
Decrease in common stock share count							300,000
Quarterly Dividends [Member]
Share-Based Compensation and Capital Stock [Line Items]
Cash dividends declared per share (in dollars per share)	$ 0.185		$ 0.555
Dividends declared	10,800,000		32,400,000
Quarterly [Member]
Share-Based Compensation and Capital Stock [Line Items]
Periodic dividend, per share			$ 0.185
Performance Vested Restricted Stock Units [Member]
Share-Based Compensation and Capital Stock [Line Items]
Grants vested	0	0	28,886		39,816
Grants vested, total fair value			1,400,000		1,300,000
Grants vested, initial target			18,635		30,624
Grants vested, performance percentage achieved			155.00%		130.00%
Increase in shares due to performance percentage achieved			10,251	[1]	9,192	[1]
Decrease in share-based compensation costs			(900,000)
Dividends paid	$ 0		$ 400,000
Performance Vested Restricted Stock Units [Member] | Minimum [Member]
Share-Based Compensation and Capital Stock [Line Items]
Vesting range (percentage)			0.00%
Award targets currently estimated to be achieved (percentage)			0.00%
Performance Vested Restricted Stock Units [Member] | Maximum [Member]
Share-Based Compensation and Capital Stock [Line Items]
Vesting range (percentage)			200.00%
Award targets currently estimated to be achieved (percentage)			150.00%

[1] PVRSU units outstanding have been increased by 10,251 units due to the Company exceeding the targeted performance conditions contained in PVRSUs granted in prior periods during the nine months ended September 30, 2014.