Stock-Based Compensation - Stock Award Information and Fair Value Assumptions (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) $ / shares shares	Mar. 31, 2016 USD ($) $ / shares
Stock-based compensation
Aggregate grant-date fair value of stock options, restricted stock awards, performance share awards and restricted stock units | $	$ 23.8
Stock-based compensation expense
Total pre-tax stock-based compensation | $	$ 6.0	$ 3.5
Weighted-average assumptions used to estimate grant date fair value of stock options
Expected dividend yield (as a percent)	1.30%	1.40%
Expected life in years	5 years 6 months 29 days	5 years 7 months 10 days
Expected volatility (as a percent)	25.60%	27.50%
Risk-free interest rate (as a percent)	1.90%	1.40%
Weighted average fair value per share (in dollars per share) | $ / shares	$ 24.57	$ 19.30
Executive Incentive Program
Stock-based compensation
Shares available for grant under the plan	3,446,278
Shares available for issuance under the plan	1,290,602
Stock options
Stock-based compensation
Options granted (in shares)	363,455
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
Total pre-tax stock-based compensation | $	$ 1.9	$ 1.6
Restricted stock awards
Stock-based compensation
Awards granted (in shares)	65,347
Performance share awards
Stock-based compensation
Awards granted (in shares)	46,995
Restricted Stock Units
Stock-based compensation
Awards granted (in shares)	12,952