Background and Basis of Presentation - EPS (Details) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($) primary_operation $ / shares shares	Mar. 31, 2019 USD ($) $ / shares shares
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Number of primary operations | primary_operation	2
Earnings (Loss) Per Basic Common Share
Income from continuing operations	$ 16.4	$ 11.8
Amounts attributable to participating securities	(0.1)	0.0
Net income available to common stockholders	$ 16.3	$ 11.8
Weighted-average basic shares outstanding (in shares) | shares	16,817,000	16,862,000
Basic earnings (in usd per share) | $ / shares	$ 0.97	$ 0.70
Earnings (Loss) Per Diluted Common Share
Income from continuing operations	$ 16.4	$ 11.8
Amounts attributable to participating securities	(0.1)	0.0
Net income available to common stockholders	$ 16.3	$ 11.8
Weighted-average diluted shares
Weighted-average basic shares outstanding (in shares) | shares	16,817,000	16,862,000
Add: Assumed incremental shares under stock compensation plans (in shares) | shares	33,000	59,000
Weighted-average diluted shares (in shares) | shares	16,850,000	16,921,000
Diluted earnings (in usd per share) | $ / shares	$ 0.97	$ 0.69
Potentially dilutive stock-based compensation awards excluded from computation of dilutive common shares (in shares) | shares	267,152	231,332