Basis of Presentation (Details) $ / shares in Units, $ in Millions				9 Months Ended
	Jan. 31, 2018 shares	Jan. 30, 2018 USD ($) $ / shares shares	Jan. 23, 2018	Sep. 30, 2018 $ / shares shares	Dec. 31, 2017 $ / shares shares
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Conversion ratio	0.1
Common stock, par value (in dollars per share) | $ / shares				$ 1	$ 1
Common stock, shares authorized (in shares)	25,000,000	250,000,000		25,000,000	25,000,000
Preferred stock, preferred stock authorized (in shares)	1,000,000			1,000,000.0
Subsidiary, Sale of Stock [Line Items]
Dividend rate (as percent)				5.00%
Series A Preferred Stock | Securities Purchase Agreement
Subsidiary, Sale of Stock [Line Items]
Number of shares issued (in shares)		9,926
Convertible preferred stock, Series A convertible par value (in dollars per share) | $ / shares		$ 1.00
Consideration received on transaction | $		$ 9.9
Dividend rate (as percent)		5.00%	5.00%
Shares issuable upon conversion (in shares)		1,001,614