Consolidated statements of changes in shareholders' equity - USD ($) $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income, net
Balance at Dec. 31, 2018	$ 671,857	$ 30,725	$ 424,146	$ 221,213	$ (4,227)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19,588			19,588
Other comprehensive income (loss), net of taxes	7,357				7,357
Stock based compensation expense	1,638	3	1,635
Restricted stock units vested and distributed, net of shares withheld	(2,373)	114	(2,487)
Shares issued under employee stock purchase program	364	11	353
Dividends declared	(2,545)			(2,545)
Balance at Mar. 31, 2019	694,577	30,853	423,647	236,947	3,130
Balance at Dec. 31, 2019	762,329	31,034	425,633	293,524	12,138
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	745			745
Other comprehensive income (loss), net of taxes	10,802				10,802
Common stock issued in connection with acquisition of FNB Financial Corp., net of registration costs	34,847	955	33,892
Stock based compensation expense	1,883	5	1,878
Restricted stock units vested and distributed, net of shares withheld	(838)	61	(899)
Shares issued under employee stock purchase program	446	12	434
Dividends declared	(2,866)			(2,866)
Balance at Mar. 31, 2020	$ 782,330	$ 32,067	$ 460,938	$ 266,385	$ 22,940