Shareholders' Equity - Schedule of Treasury Stock (Details) - shares	12 Months Ended		14 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017
Movement in Treasury Stock [Roll Forward]
Treasury shares, beginning balance (in shares)	744,091	715,947
Purchases (in shares)	27,950	24,086	100,000
Exercise of stock options (in shares)		(722)
Restricted stock grants and other (in shares)	(138,102)	4,780
Treasury shares, ending balance (in shares)	633,939	744,091	633,939