Stock-Based Compensation - Stock Award Information and Fair Value Assumptions (Details) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($) shares	Jun. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) $ / shares shares	Jun. 30, 2015 USD ($) $ / shares
Stock-based compensation
Aggregate grant-date fair value of stock options, restricted stock awards, performance share awards and restricted stock units | $			$ 21.6
Stock-based compensation expense
Pre-tax compensation expense | $	$ 3.9	$ 3.3	$ 8.6	$ 11.6
Weighted-average assumptions used to estimate grant date fair value of stock options
Expected dividend yield (as a percent)			1.40%	1.10%
Expected life in years			5 years 7 months 10 days	5 years 8 months 16 days
Expected volatility (as a percent)			27.50%	27.30%
Risk-free interest rate (as a percent)			1.40%	1.40%
Weighted average fair value (in dollars per share) | $ / shares			$ 19.30	$ 21.19
Executive Incentive Program
Stock-based compensation
Shares available for grant under the plan	3,936,710		3,936,710
Shares available for issuance under the plan	1,433,660		1,433,660
Stock options
Stock-based compensation
Stock options granted (in shares)			371,623
Portion of stock options vesting on the first anniversary			0.3333
Portion of stock options vesting on the second anniversary			0.3333
Portion of stock options vesting on the third anniversary			0.3333
Maximum term life			10 years
Stock-based compensation expense
Pre-tax compensation expense | $	$ 1.4	$ 1.2	$ 3.0	$ 2.5
Restricted stock awards
Stock-based compensation
Awards granted (in shares)			69,583
Performance share awards
Stock-based compensation
Awards granted (in shares)			61,127
Restricted Stock Units
Stock-based compensation
Awards granted (in shares)			13,466