FAIR VALUE MEASUREMENT - Schedule of Fair Value Hierarchy Measurement (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Assets:
Investment securities AFS	$ 1,354,198	$ 1,378,774
Single family mortgage servicing rights	76,314
Derivatives	755	893
Liabilities:
Derivative liabilities	13,117	13,179
Residential mortgage-backed securities
Assets:
Investment securities AFS	191,618	197,262
Commercial mortgage-backed securities
Assets:
Investment securities AFS	53,231	56,049
Municipal bonds
Assets:
Investment securities AFS	405,545	411,548
Corporate debt securities
Assets:
Investment securities AFS	39,023	42,945
U.S. Treasury securities
Assets:
Investment securities AFS	19,868	19,934
Agency debentures
Assets:
Investment securities AFS	60,368	27,478
Recurring
Assets:
Single family LHFS	30,384	14,075
Single family LHFI	1,269	5,868
Single family mortgage servicing rights	76,314	76,617
Total assets	1,516,455	1,508,094
Liabilities:
Total liabilities	13,202	13,280
Recurring | Residential mortgage-backed securities
Assets:
Investment securities AFS	191,618	197,262
Recurring | Commercial mortgage-backed securities
Assets:
Investment securities AFS	53,231	56,049
Recurring | Collateralized mortgage obligations residential
Assets:
Investment securities AFS	518,191	553,039
Recurring | Collateralized mortgage obligations commercial
Assets:
Investment securities AFS	66,354	70,519
Recurring | Municipal bonds
Assets:
Investment securities AFS	405,545	411,548
Recurring | Corporate debt securities
Assets:
Investment securities AFS	39,023	42,945
Recurring | U.S. Treasury securities
Assets:
Trading securities - U.S. Treasury securities	40,447	18,997
Investment securities AFS	19,868	19,934
Recurring | Agency debentures
Assets:
Investment securities AFS	60,368	27,478
Recurring | Futures
Assets:
Derivatives	5	18
Recurring | Forward sale commitments
Assets:
Derivatives	520	293
Liabilities:
Derivative liabilities	199	151
Recurring | Options
Assets:
Derivatives	237	218
Recurring | Interest rate lock commitments
Assets:
Derivatives	226	141
Liabilities:
Derivative liabilities	147	36
Recurring | Interest rate swaps
Assets:
Derivatives	12,855	13,093
Liabilities:
Derivative liabilities	12,856	13,093
Level 1 | Recurring
Assets:
Single family LHFS	0	0
Single family LHFI	0	0
Single family mortgage servicing rights	0	0
Total assets	40,689	19,233
Liabilities:
Total liabilities	0	0
Level 1 | Recurring | Residential mortgage-backed securities
Assets:
Investment securities AFS	0	0
Level 1 | Recurring | Commercial mortgage-backed securities
Assets:
Investment securities AFS	0	0
Level 1 | Recurring | Collateralized mortgage obligations residential
Assets:
Investment securities AFS	0	0
Level 1 | Recurring | Collateralized mortgage obligations commercial
Assets:
Investment securities AFS	0	0
Level 1 | Recurring | Municipal bonds
Assets:
Investment securities AFS	0	0
Level 1 | Recurring | Corporate debt securities
Assets:
Investment securities AFS	0	0
Level 1 | Recurring | U.S. Treasury securities
Assets:
Trading securities - U.S. Treasury securities	40,447	18,997
Investment securities AFS	0	0
Level 1 | Recurring | Agency debentures
Assets:
Investment securities AFS	0	0
Level 1 | Recurring | Futures
Assets:
Derivatives	5	18
Level 1 | Recurring | Forward sale commitments
Assets:
Derivatives	0	0
Liabilities:
Derivative liabilities	0	0
Level 1 | Recurring | Options
Assets:
Derivatives	237	218
Level 1 | Recurring | Interest rate lock commitments
Assets:
Derivatives	0	0
Liabilities:
Derivative liabilities	0	0
Level 1 | Recurring | Interest rate swaps
Assets:
Derivatives	0	0
Liabilities:
Derivative liabilities	0	0
Level 2 | Recurring
Assets:
Single family LHFS	30,384	14,075
Single family LHFI	0	0
Single family mortgage servicing rights	0	0
Total assets	1,396,044	1,404,226
Liabilities:
Total liabilities	13,055	13,244
Level 2 | Recurring | Residential mortgage-backed securities
Assets:
Investment securities AFS	189,705	195,321
Level 2 | Recurring | Commercial mortgage-backed securities
Assets:
Investment securities AFS	53,231	56,049
Level 2 | Recurring | Collateralized mortgage obligations residential
Assets:
Investment securities AFS	518,191	553,039
Level 2 | Recurring | Collateralized mortgage obligations commercial
Assets:
Investment securities AFS	66,354	70,519
Level 2 | Recurring | Municipal bonds
Assets:
Investment securities AFS	405,545	411,548
Level 2 | Recurring | Corporate debt securities
Assets:
Investment securities AFS	39,023	42,877
Level 2 | Recurring | U.S. Treasury securities
Assets:
Trading securities - U.S. Treasury securities	0	0
Investment securities AFS	19,868	19,934
Level 2 | Recurring | Agency debentures
Assets:
Investment securities AFS	60,368	27,478
Level 2 | Recurring | Futures
Assets:
Derivatives	0	0
Level 2 | Recurring | Forward sale commitments
Assets:
Derivatives	520	293
Liabilities:
Derivative liabilities	199	151
Level 2 | Recurring | Options
Assets:
Derivatives	0	0
Level 2 | Recurring | Interest rate lock commitments
Assets:
Derivatives	0	0
Liabilities:
Derivative liabilities	0	0
Level 2 | Recurring | Interest rate swaps
Assets:
Derivatives	12,855	13,093
Liabilities:
Derivative liabilities	12,856	13,093
Level 3 | Recurring
Assets:
Single family LHFS	0	0
Single family LHFI	1,269	5,868
Single family mortgage servicing rights	76,314	76,617
Total assets	79,722	84,635
Liabilities:
Total liabilities	147	36
Level 3 | Recurring | Residential mortgage-backed securities
Assets:
Investment securities AFS	1,913	1,941
Level 3 | Recurring | Commercial mortgage-backed securities
Assets:
Investment securities AFS	0	0
Level 3 | Recurring | Collateralized mortgage obligations residential
Assets:
Investment securities AFS	0	0
Level 3 | Recurring | Collateralized mortgage obligations commercial
Assets:
Investment securities AFS	0	0
Level 3 | Recurring | Municipal bonds
Assets:
Investment securities AFS	0	0
Level 3 | Recurring | Corporate debt securities
Assets:
Investment securities AFS	0	68
Level 3 | Recurring | U.S. Treasury securities
Assets:
Trading securities - U.S. Treasury securities	0	0
Investment securities AFS	0	0
Level 3 | Recurring | Agency debentures
Assets:
Investment securities AFS	0	0
Level 3 | Recurring | Futures
Assets:
Derivatives	0	0
Level 3 | Recurring | Forward sale commitments
Assets:
Derivatives	0	0
Liabilities:
Derivative liabilities	0	0
Level 3 | Recurring | Options
Assets:
Derivatives	0	0
Level 3 | Recurring | Interest rate lock commitments
Assets:
Derivatives	226	141
Liabilities:
Derivative liabilities	147	36
Level 3 | Recurring | Interest rate swaps
Assets:
Derivatives	0	0
Liabilities:
Derivative liabilities	$ 0	$ 0