Share Repurchase Plan (Details) - USD ($)	6 Months Ended		26 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	May 31, 2016
Equity [Abstract]
Amount authorized by the company's Board of Directors (not more than)				$ 30,000,000
Common stock repurchased under share repurchase program (in shares)	0	0	305,183
Average cost per share (in dollars per share)			$ 24.43
Amount of program-to-date purchases			$ 7,500,000