Shareholders’ Equity and Earnings Per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of factors used in computing basic and diluted earnings per common share
Net income available to common shareholders					$ 7,215	$ 6,261	$ 6,791	$ 5,602	$ 23,828	$ 25,869	$ 14,705
Less: undistributed earnings allocated to Series C Preferred Stock						(300)	(575)	(403)		(1,278)	(912)
Distributed and undistributed earnings allocated to common shareholders					$ 7,215	$ 5,961	$ 6,216	$ 5,199	$ 23,828	$ 24,591	$ 13,793
Weighted average common shares outstanding for basic earnings per common share (in shares)									38,095,250	33,933,806	28,567,213
Dilutive effect of stock options outstanding, using the treasury stock method (in shares)									515,565	285,315	218,865
Shares used in computing diluted earnings per common share (in shares)									38,610,815	34,219,121	28,786,078
Basic earnings per share (in dollars per share)	$ 0.03	$ 0.22	$ 0.20	$ 0.17	$ 0.19	$ 0.18	$ 0.19	$ 0.16	$ 0.63	$ 0.72	$ 0.48
Diluted earnings per share (in dollars per share)	$ 0.03	$ 0.22	$ 0.19	$ 0.17	$ 0.19	$ 0.18	$ 0.19	$ 0.16	$ 0.62	$ 0.72	$ 0.48