Stock-Based Compensation, Stock Award and Incentive Plan and Stock Options (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee service share-based compensation, aggregate disclosures [Abstract]
Number of common stock available for issuance (in shares)	880,000
Term of stock options granted under Plan	10 years
Vesting period, generally, for stock options granted under the plan	3 years
Share based compensation costs	$ 6.2	$ 8.1	$ 6.3
Stock Options [Member]
Employee service share-based compensation, aggregate disclosures [Abstract]
Share based compensation costs	4.2	4.1	3.5
Tax benefit of share-based compensation	$ 1.1	$ 1.1	$ 1.4
Forfeiture rate assumed	8.20%	8.71%	7.38%
Weighted average grant date fair value for stock options granted (in dollars per share)	$ 25.79	$ 30.28	$ 14.34
Weighted average grant date fair value for stock options vested (in dollars per share)	$ 21.33	$ 18.45	$ 20.94
Total intrinsic value of stock options exercised	$ 3.3	$ 11.7	$ 4.9
Weighted Average Assumptions [Abstract]
Expected life	6 years 2 months 12 days	6 years 4 months 24 days	6 years 6 months
Interest rate	2.50%	2.04%	1.72%
Volatility	30.33%	36.61%	36.75%
Expected dividend yield	0.26%	0.26%	0.54%
Stock Options [Roll Forward]
Balance, beginning of year (in shares)	996,839
Granted (in shares)	191,147
Exercised (in shares)	(98,945)
Canceled (in shares)	(34,782)
Balance, end of year (in shares)	1,054,259	996,839
Exercisable, end of year (in shares)	688,652
Weighted Average Exercise Price Per Share [Abstract]
Balance, beginning of year (in dollars per share)	$ 48.21
Granted (in dollars per share)	76.09
Exercised (in dollars per share)	33.83
Canceled (in dollars per share)	65.74
Balance, end of year (in dollars per share)	54.04	$ 48.21
Exercisable, end of year (in dollars per share)	$ 46.17
Weighted Average Remaining Contractual Life [Abstract]
Outstanding options, end of year	6 years 1 month 6 days
Exercisable options, end of year	4 years 10 months 24 days
Aggregate Intrinsic Value [Abstract]
Outstanding options, end of year	$ 7.8
Exercisable options, end of year	$ 6.9
Additional Information [Abstract]
Closing stock price on last business day of the period (in dollars per share)	$ 51.34
Weighted average intrinsic value of options exercised (in dollars per share)	$ 33.10	$ 32.95	$ 32.34
Unrecognized stock-based compensation expense	$ 4.5
Weighted average period over which unrecognized stock-based compensation expense is expected to be recognized	3 years
Nonvested Stock Options [Member]
Stock Options [Roll Forward]
Balance, beginning of year (in shares)	400,393
Granted (in shares)	191,147
Vested (in shares)	(195,055)
Canceled (in shares)	(30,878)
Balance, end of year (in shares)	365,607	400,393
Weighted Average Exercise Price Per Share [Abstract]
Balance, beginning of year (in dollars per share)	$ 58.94
Granted (in dollars per share)	76.09
Vested (in dollars per share)	56.17
Canceled (in dollars per share)	65.13
Balance, end of year (in dollars per share)	$ 68.86	$ 58.94