Shareholders' Equity - Additional Information (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Stockholders' Equity Note [Abstract]
Common stock repurchased, shares	0	0
Common stock repurchased, value	$ 7,446
Shares are available for future issuances	$ 17,554
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures	0	0
Antidilutive securities excluded from computation of earnings per share (shares)	1,538	10,094