Stock-Based Compensation Changes in Outstanding Stock Options (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance share awards, expected target	100.00%	179.00%	200.00%
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options or share units	65,165	113,216	154,016	190,256
Number of options or share units, granted	0	0	0
Stock-options exercised, shares	(48,051)	(40,800)	(31,630)
Number of options or share units, forfeited			(4,610)
Number of exercisable options or share units	65,165
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price	$ 25.96
Weighted average exercise price, outstanding	25.96	$ 24.21	$ 23.65	$ 23.71
Weighted average exercise price, exercises	$ 21.84	$ 22.08	26.98
Weighted average exercise price, forfeitures			$ 25.37
Weighted average remaining contractual life	8 months 12 days	1 year 2 months 12 days	1 year 8 months 12 days	2 years 8 months 12 days
Options exercised, intrinsic value	$ 0.6	$ 0.8	$ 0.6
Options vested, fair value	0.0	0.1	0.2
Options exercisable, intrinsic value	1.0	0.9	2.7
Options outstanding, intrinsic value	$ 1.0	$ 0.9	$ 2.8
Stock Options Exercisable [Domain]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining contractual life	8 months 12 days
Restricted stock units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options or share units	198,126	244,344	241,905	250,300
Number of options or share units, granted	86,020	100,491	90,576
Share-based Compensation Arrangements by Share-based Payment Award, Options, Grants in Period, Weighted Average Exercise Price	$ 38.29	$ 36.01	$ 40.60
Number of options or share units, forfeited	(35,730)	(7,710)	(22,232)
Number of vested options or share units	(96,508)	(90,342)	(76,739)
Weighted average exercise price, forfeitures	$ 38.78	$ 38.94	$ 36.39
Weighted average grant date fair value	34.53	35.08	32.45	$ 32.45
Weighted average exercise price, vested	$ 37.71	$ 34.76	$ 33.99
Share-based compensation expense, deferred	$ 3.8
Share-based compensation expense, Period for Recognition	39 months
Service vesting period for options awarded	4 years
Vesting rights for options awarded	vest 25% on or after each of the subsequent four anniversaries of such date
Options vested, fair value	$ 3.6	$ 3.1	$ 2.6
Options exercisable, intrinsic value	3.8	3.0	3.2
Options outstanding, intrinsic value	$ 8.2	$ 7.9	$ 10.1
Restricted Stock Units Vested but Unsettled [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of outstanding options or share units	68,023
Weighted average grant date fair value	$ 26.83

Performance share awards, based on the expectation of the Company achieving a target rate.

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