LEASES - Right-of-use Assets and Lease Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended			12 Months Ended
	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2019	Jan. 01, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cash paid for operating lease liabilities				$ 1,122
Operating lease right-of-use assets				$ 10,485
Weighted-average remaining lease term (in years)	17 years 7 months 6 days			17 years 7 months 6 days
Weighted-average discount rate	4.50%			4.50%
Operating lease liabilities	$ 9,688			$ 9,688
Operating Leases that commenced			$ 144
Removal of operating leases	988
Bank Branch Consolidations
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Removal of operating leases	$ 423
Hamilton Bancorp, Inc.
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating Leases that commenced		$ 2,800
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease liabilities					$ 8,000