INCOME TAXES - Differences Between Federal Income Tax And Actual Income Tax (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
INCOME TAXES
Statutory tax rate (as a percent)									21.00%	21.00%	35.00%
Differences between the statutory federal income tax and the actual income tax provision (benefit)
Statutory federal tax provision									$ 4,762	$ 2,983	$ 5,968
Increase (decrease) resulting from:
State taxes, net of federal tax benefit									866	772	694
Bank-owned life insurance									(232)	(358)	(359)
Non-deductible merger expenses										196
Employee Stock Ownership Plan expenses									172	106	195
Tax exempt income									(104)	(180)	(303)
Effect of tax rate change											243
Reduction in uncertain tax positions									(1,586)	(801)
Other, net									530	95	235
Income tax provision	$ 2,180	$ 1,053	$ 819	$ 356	$ 236	$ 818	$ 945	$ 814	$ 4,408	$ 2,813	$ 6,673