Discontinued Operations - EPS (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended
	Mar. 31, 2017	Sep. 30, 2016	Mar. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements			882
Income (Loss) Allocated to Participating Unvested Restricted Common Shares	$ 0.4		$ 0.1
Net Income (Loss) Available to Common Stockholders, Basic	$ 34.3		$ 13.0
Total average common shares outstanding during the period	4,564,600		5,539,600
Average unvested restricted common shares	(52,500)		(54,000)
Basic earnings per share denominator	4,512,100		5,485,600
Average outstanding dilutive options to acquire common shares	4,564,600		5,540,500
Diluted earnings (loss) per share denominator	4,512,100		5,486,500
Earnings Per Share, Diluted	$ 7.50		$ 2.34
Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net loss from discontinued operations, net of tax	$ (1.0)		$ 1.1
Income (Loss) Allocated to Participating Unvested Restricted Common Shares	0.0		0.0
Net Income (Loss) Available to Common Stockholders, Basic	$ (1.0)		$ 1.1
Total average common shares outstanding during the period	4,564,600		5,540,500
Average unvested restricted common shares	(52,500)		(54,000)
Basic earnings per share denominator	4,512,100		5,485,600
Diluted earnings (loss) per share denominator	4,512,100		5,486,500
Earnings Per Share, Basic	$ (0.22)		$ 0.20
Earnings Per Share, Diluted	$ (0.22)		$ 0.20
Employee Stock Option [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements		120,000