Background and Basis of Presentation - EPS (Details) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) $ / shares shares	Jun. 30, 2019 USD ($) $ / shares shares	Jun. 30, 2020 USD ($) primary_operation $ / shares shares	Jun. 30, 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 (loss) from continuing operations | $	$ (50.1)	$ 13.6	$ (33.7)	$ 25.4
Amounts attributable to participating securities | $	0.0	(0.1)	(0.1)	(0.2)
Net income (loss) available to common stockholders | $	$ (50.1)	$ 13.5	$ (33.8)	$ 25.2
Weighted-average basic shares outstanding (in shares) | shares	16,797,000	16,863,000	16,812,000	16,861,000
Basic earnings (loss) (in usd per share) | $ / shares	$ (2.98)	$ 0.80	$ (2.01)	$ 1.50
Earnings (Loss) Per Diluted Common Share
Income (loss) from continuing operations | $	$ (50.1)	$ 13.6	$ (33.7)	$ 25.4
Amounts attributable to participating securities | $	0.0	(0.1)	(0.1)	(0.2)
Net income (loss) available to common stockholders | $	$ (50.1)	$ 13.5	$ (33.8)	$ 25.2
Weighted-average diluted shares
Weighted-average basic shares outstanding (in shares) | shares	16,797,000	16,863,000	16,812,000	16,861,000
Add: Assumed incremental shares under stock compensation plans (in shares) | shares	0	47,000	0	53,000
Weighted-average diluted shares (in shares) | shares	16,797,000	16,910,000	16,812,000	16,914,000
Diluted earnings (loss) (in usd per share) | $ / shares	$ (2.98)	$ 0.80	$ (2.01)	$ 1.49
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) | shares	338,690	230,928	340,886	231,129
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) | shares	23,000		28,000