Shareholders' Equity - Treasury Stock (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended		11 Months Ended
	Sep. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Nov. 14, 2016	May 02, 2012
Equity [Abstract]
Number of shares authorized to be repurchased (in shares)					500,000.0	500,000
Number of shares repurchased (in shares)	27,950	27,950		52,036
Payments for repurchase of common stock		$ 0.1	$ 0.2	$ 0.3
Remaining number of shares authorized to be repurchased (in shares)	447,964	447,964		447,964
Average price per share of treasury stock acquired and held (in dollars per share)		$ 37.82
Movement in Treasury Stock [Roll Forward]
Beginning balance (in shares)		744,091
Purchases (in shares)	27,950	27,950		52,036
Restricted stock grants (in shares)		(86,000)
Forfeitures and other (in shares)		67,767
Ending balance (in shares)	753,808	753,808		753,808