CONDENSED PARENT COMPANY ONLY FINANCIAL STATEMENTS - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	1 Months Ended	12 Months Ended
	Oct. 31, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities:
Net income		$ 44,718	$ 41,334	$ 31,897
Adjustments to reconcile net income to net cash provided by operating activities:
Increase in other assets		480	2,644	(3,687)
Net cash flow provided (used) by operating activities		32,199	(160,991)	151,812
Cash flow froms investing activities:
Net cash flow (used) provided by investing activities		(18,289)	109,410	(277,942)
Cash flows from financing activities:
Issuance of common stock, net of expenses	$ 13,900	13,911
Exercise of stock options				685
Repurchase of common stock		(1,485)
Dividends paid on common stock		(10,367)	(9,291)	(5,401)
Net cash flow provided by financing activities		124,076	94,175	155,399
Net change in cash and cash equivalents		137,986	42,594	29,269
Cash and cash equivalents at beginning of period		138,427	95,833	66,564
Cash and cash equivalents at end of period		276,413	138,427	95,833
Parent company
Cash flows from operating activities:
Net income		44,718	41,334	31,897
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed net income of subsidiary		(34,416)	(32,086)	(26,444)
Increase in other assets		938	(924)	(135)
Decrease in accrued expenses and other liabilities		92	42	(68)
Net cash flow provided (used) by operating activities		11,332	8,366	5,250
Cash flows from financing activities:
Issuance of common stock, net of expenses		13,911
Exercise of stock options				685
Repurchase of common stock		(1,485)
Dividends paid on common stock		(10,367)	(9,224)	(5,401)
Net cash flow provided by financing activities		2,059	(9,224)	(4,716)
Net change in cash and cash equivalents		13,391	(858)	534
Cash and cash equivalents at beginning of period		2,600	3,458	2,924
Cash and cash equivalents at end of period		$ 15,991	$ 2,600	$ 3,458