ACQUISITIONS - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020	Feb. 04, 2020	Dec. 31, 2019
Liabilities:
Goodwill	$ 38,838	$ 38,838		$ 35,466
Grand Mountain Bancshares, Inc.
Liabilities:
Fair value of net assets acquired			$ 10,348
Goodwill			3,372
Grand Mountain Bancshares, Inc. | Previously Reported
Fair value of assets:
Cash and due from banks			5,454
Total cash and cash equivalents			5,454
Interest bearing deposits in banks			16,040
Investment securities available-for-sale			4,369
FHLB stock, at par			165
Loans, net			98,410
Premises and equipment, net			3,879
Core deposit intangible			949
Deferred tax assets, net			728
Interest receivable and other assets			929
Total assets acquired			130,923
Liabilities:
Noninterest bearing			30,937
Interest bearing			87,210
Total Deposits			118,147
Interest payable and other liabilities			687
Other borrowings			1,575
Total liabilities assumed			120,409
Fair value of net assets acquired			10,514
Grand Mountain Bancshares, Inc. | Revision of Prior Period, Adjustment
Fair value of assets:
Investment securities available-for-sale			10
Loans, net			484
Premises and equipment, net			(1,000)
Core deposit intangible			949
Deferred tax assets, net			139
Time deposits			(25)
Liabilities:
Other borrowings			(98)
Other (assets) liabilities			5
Fair value of net assets acquired			$ 166