CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS EQUITY - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2016	$ 382,658	$ 25,441		$ 313,552	$ 50,933	$ (7,268)
Beginning balance, shares at Dec. 31, 2016		25,441	24,616,706
Net income	22,461				22,461
Other comprehensive income (loss), net of tax	2,720					2,720
Issuance of common stock in connection with merger			$ 246	(246)
Repurchase of preferred stock	(15,003)	$ (15,003)
Repurchase of preferred stock, shares		(15,003)
Issuance of common stock, net of issuance costs	76,829		$ 46	76,783
Issuance of common stock, net of issuance cost, shares			4,630,194
Issuance of common stock in connection with restricted stock awards, shares			58,900
Forfeiture of restricted stock awards, shares			(400)
Cash dividends declared on preferred stock	(11,081)				(11,081)
Cash paid in lieu of fractional shares	(2)				(2)
Share-based compensation expense	951			951
Ending balance at Sep. 30, 2017	459,533	$ 10,438	$ 292	391,040	62,311	(4,548)
Ending balance, shares at Sep. 30, 2017		10,438	29,305,400
Beginning balance at Dec. 31, 2016	382,658	$ 25,441		313,552	50,933	(7,268)
Beginning balance, shares at Dec. 31, 2016		25,441	24,616,706
Ending balance at Dec. 31, 2017	458,578	$ 10,438	$ 292	391,586	61,349	(5,087)
Ending balance, shares at Dec. 31, 2017		10,438	29,317,298
Net income	24,072				24,072
Other comprehensive income (loss), net of tax	(6,512)					(6,512)
Issuance of common stock upon exercise of stock options	1,702		$ 2	1,700
Issuance of common stock upon exercise of stock options, shares			146,513
Issuance of common stock and stock options due to business combination, net of issuance costs	151,275		$ 67	151,208
Issuance of common stock and stock options due to business combination, net of issuance costs, shares			6,682,850
Issuance of common stock in connection with restricted stock awards, shares			126,157
Forfeiture of restricted stock awards, shares			(2,100)
Issuance of common stock in connection with employee stock purchase plan	172			172
Issuance of common stock in connection with employee stock purchase plan, shares			8,882
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)	(763)				763	(763)
Cash dividends declared on preferred stock	(587)				(587)
Share-based compensation expense	1,161			1,161
Ending balance at Sep. 30, 2018	$ 629,861	$ 10,438	$ 361	$ 545,827	$ 85,597	$ (12,362)
Ending balance, shares at Sep. 30, 2018		10,438	36,279,600