Background and Basis of Presentation - EPS (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings (Loss) Per Basic Common Share
Income (loss) from continuing operations	$ 7.9	$ 14.4	$ (25.8)	$ 39.8
Amounts attributable to participating securities	(0.1)	(0.1)	(0.2)	(0.2)
Net income (loss) available to common stockholders	$ 7.8	$ 14.3	$ (26.0)	$ 39.6
Weighted-average basic shares outstanding (in shares)	16,802,000	16,837,000	16,810,000	16,850,000
Basic earnings (loss) (in usd per share)	$ 0.46	$ 0.85	$ (1.55)	$ 2.35
Earnings (Loss) Per Diluted Common Share
Income (loss) from continuing operations	$ 7.9	$ 14.4	$ (25.8)	$ 39.8
Amounts attributable to participating securities	(0.1)	(0.1)	(0.2)	(0.2)
Net income (loss) available to common stockholders	$ 7.8	$ 14.3	$ (26.0)	$ 39.6
Weighted-average diluted shares
Weighted-average basic shares outstanding (in shares)	16,802,000	16,837,000	16,810,000	16,850,000
Add: Assumed incremental shares under stock compensation plans (in shares)	19,000	68,000	0	60,000
Weighted-average diluted shares (in shares)	16,821,000	16,905,000	16,810,000	16,910,000
Diluted earnings (loss) (in usd per share)	$ 0.46	$ 0.84	$ (1.55)	$ 2.33
Dilutive Options
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive stock-based compensation awards excluded from computation of dilutive common shares (in shares)	330,789	231,471	337,180	231,199
Dilutive Options and Performance Share Units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Potentially dilutive stock-based compensation awards excluded from computation of dilutive common shares (in shares)			25,626