Equity Incentive Program (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for grant under 2012 Plan	17,000,000		17,000,000
Stock-based compensation expense [Abstract]
Pre-tax compensation expense	$ 7,081	$ 7,483	$ 23,384	$ 23,589
Tax benefit	(2,493)	(2,643)	(8,241)	(8,330)
Total stock-based compensation expense, net of tax	$ 4,588	$ 4,840	$ 15,143	$ 15,259
Stock Appreciation Rights [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued during period (in shares)			1,613,884	1,719,943
Risk-free interest rate (in hundredths)			1.39%	1.05%
Dividend yield (in hundredths)			2.06%	2.03%
Expected life (in years)			7 years 1 month	5 years 8 months
Volatility (in hundredths)			33.78%	36.41%
Grant price (in dollars per share)			$ 71.86	$ 65.38
Fair value at date of grant (in dollars per share)			$ 20.62	$ 18.51
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares issued during period (in shares)			47,032	50,416
Risk-free interest rate (in hundredths)			0.40%	0.37%
Dividend yield (in hundredths)			2.06%	2.03%
Expected life (in years)			2 years 11 months	2 years 11 months
Volatility (in hundredths)			30.36%	34.10%
Fair value at date of grant (in dollars per share)			$ 80.47	$ 71.98