Share-Based Compensation and Capital Stock Summary of Change in Stock-Based Award Activity (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding at January 1, 2012 - Shares				1,573,726
Granted - Shares	0		0	160,408		166,306
Special Dividend Adjustment				497,497
Exercised/Vested - Shares	(109,996)		(26,614)	(135,200)		(164,150)
Forfeited/Expired - Shares				(30,843)
Outstanding at September 30, 2012 - Shares	2,065,588			2,065,588
Options exercisable at September 30, 2012 - Shares	1,434,178			1,434,178
Outstanding at January 1, 2012 - Weighted average exercise price				$ 33.30	[1]
Granted - Weighted average exercise price				$ 35.60	[1]
Special Dividend Adjustment - Weighted average grant date fair value				$ 25.31	[1]
Exercised/Vested - Weighted average exercise price				$ 34.73	[1]
Forfeited/Expired - Weighted average exercise price				$ 36.97	[1]
Outstanding at September 30, 2012 - Weighted average exercise price	$ 25.31	[1]		$ 25.31	[1]
Options exercisable at September 30, 2012 - Weighted average exercise price	$ 24.94	[1]		$ 24.94	[1]
Weighted Average Remaining Contractual Term - Options Oustanding at September 30, 2012				4 years 1 month 6 days
Weighted Average Remaining Contractual Term - Options Exercisable at September 30, 2012				3 years 3 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Special Dividend Adjustment				497,497
Special Dividend Adjustment - Weighted average grant date fair value				$ 25.31	[1]
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Special Dividend Adjustment				0
Special Dividend Adjustment - Weighted average grant date fair value				$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Outstanding at January 1, 2012 - Shares				565,627
Granted - shares	7,672		45,674	266,159		247,298
Special Dividend Adjustment				0
Exercised/Vested - Shares				(198,290)
Forfeited/Expired - Shares	(13,619)		(5,884)	(23,921)		(33,252)
Outstanding at September 30, 2012 - Shares	609,575			609,575
Outstanding at January 1, 2012 - Weighted average grant date fair value				$ 34.43
Granted - Weighted average grant date fair value	$ 32.59		30.27	$ 35.76		38.84
Special Dividend Adjustment - Weighted average grant date fair value				$ 0
Exercised/Vested - Weighted average grant date fair value				$ 33.75
Forfeited/Expired - Weighted average grant date fair value				$ 36.10
Outstanding at September 30, 2012 - Weighted average grant date fair value	$ 35.17			$ 35.17
Performance Vested Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Special Dividend Adjustment				0
Special Dividend Adjustment - Weighted average grant date fair value				$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Outstanding at January 1, 2012 - Shares				109,769
Granted - shares	6,137		0	100,046		25,036
Special Dividend Adjustment				0
Exercised/Vested - Shares	0		0	0		0
Forfeited/Expired - Shares	0		0	(57,176)		(41,512)
Outstanding at September 30, 2012 - Shares	152,639			152,639
Outstanding at January 1, 2012 - Weighted average grant date fair value				$ 35.57
Granted - Weighted average grant date fair value	$ 32.59		0.00	$ 35.68		41.25
Special Dividend Adjustment - Weighted average grant date fair value				$ 0
Exercised/Vested - Weighted average grant date fair value				$ 0
Forfeited/Expired - Weighted average grant date fair value				$ 34.98
Outstanding at September 30, 2012 - Weighted average grant date fair value	$ 35.86			$ 35.86

[1] The weighted average exercise price for options outstanding and exercisable reflect the reduction of the option price for outstanding options as described under "Special Dividend Adjustment". The weighted average exercise price for options granted, exercised or forfeited reflects the option price in effect at the time of the transaction.