LOANS AND ALLOWANCE FOR CREDIT LOSSES - Summary of Loans by Risk Category and Past Due Status (Details) $ in Thousands	Sep. 30, 2021 USD ($)
2021 YTD	$ 440,392
2020	750,817
2019	720,685
2018	651,175
2017	415,180
Prior	906,643
Revolving Loans	214,149
Total	4,099,041
Satisfactory
2021 YTD	440,392
2020	750,421
2019	718,603
2018	651,007
2017	403,365
Prior	870,757
Revolving Loans	213,055
Total	4,047,600
Watch
2021 YTD	0
2020	379
2019	1,946
2018	154
2017	11,561
Prior	29,485
Revolving Loans	101
Total	43,626
Special Mention
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Classified
2021 YTD	0
2020	17
2019	136
2018	14
2017	254
Prior	6,401
Revolving Loans	993
Total	7,815
Commercial Real Estate
2021 YTD	48,732
2020	136,887
2019	230,186
2018	233,465
2017	227,622
Prior	603,031
Revolving Loans	27,692
Total	1,507,615
Commercial Real Estate \| Satisfactory
2021 YTD	48,732
2020	136,508
2019	229,604
2018	233,465
2017	216,067
Prior	573,099
Revolving Loans	27,692
Total	1,465,167
Commercial Real Estate \| Watch
2021 YTD	0
2020	379
2019	582
2018	0
2017	11,555
Prior	25,666
Revolving Loans	0
Total	38,182
Commercial Real Estate \| Special Mention
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Commercial Real Estate \| Classified
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	4,266
Revolving Loans	0
Total	4,266
Consumer Loan
2021 YTD	16,323
2020	13,123
2019	8,724
2018	11,439
2017	5,414
Prior	28,793
Revolving Loans	128,539
Total	212,355
Consumer Loan \| Satisfactory
2021 YTD	16,323
2020	13,106
2019	8,724
2018	11,403
2017	5,349
Prior	28,451
Revolving Loans	128,133
Total	211,489
Consumer Loan \| Watch
2021 YTD	0
2020	0
2019	0
2018	22
2017	6
Prior	15
Revolving Loans	29
Total	72
Consumer Loan \| Special Mention
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Consumer Loan \| Classified
2021 YTD	0
2020	17
2019	0
2018	14
2017	59
Prior	327
Revolving Loans	377
Total	794
One- to four-family residential construction
2021 YTD	16,340
2020	6,655
2019	724
2018	0
2017	0
Prior	5
Revolving Loans	0
Total	23,724
One- to four-family residential construction \| Satisfactory
2021 YTD	16,340
2020	6,655
2019	724
2018	0
2017	0
Prior	5
Revolving Loans	0
Total	23,724
One- to four-family residential construction \| Watch
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
One- to four-family residential construction \| Special Mention
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
One- to four-family residential construction \| Classified
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Subdivision construction
2021 YTD	4,928
2020	1,005
2019	237
2018	193
2017	791
Prior	1,034
Revolving Loans	0
Total	8,188
Subdivision construction \| Satisfactory
2021 YTD	4,928
2020	1,005
2019	237
2018	193
2017	791
Prior	1,018
Revolving Loans	0
Total	8,172
Subdivision construction \| Watch
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Subdivision construction \| Special Mention
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Subdivision construction \| Classified
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	16
Revolving Loans	0
Total	16
Construction and land development
2021 YTD	4,139
2020	19,792
2019	11,203
2018	2,609
2017	3,025
Prior	6,069
Revolving Loans	1,023
Total	47,860
Construction and land development \| Satisfactory
2021 YTD	4,139
2020	19,792
2019	11,203
2018	2,609
2017	3,025
Prior	6,069
Revolving Loans	555
Total	47,392
Construction and land development \| Watch
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Construction and land development \| Special Mention
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Construction and land development \| Classified
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	468
Total	468
Other Construction
2021 YTD	74,248
2020	304,277
2019	161,445
2018	41,036
2017	0
Prior	0
Revolving Loans	0
Total	581,006
Other Construction \| Satisfactory
2021 YTD	74,248
2020	304,277
2019	161,445
2018	41,036
2017	0
Prior	0
Revolving Loans	0
Total	581,006
Other Construction \| Watch
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Other Construction \| Special Mention
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Other Construction \| Classified
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
One- to four-family residential
2021 YTD	186,774
2020	183,093
2019	106,187
2018	56,148
2017	15,398
Prior	125,635
Revolving Loans	1,906
Total	675,141
One- to four-family residential \| Satisfactory
2021 YTD	186,774
2020	183,093
2019	104,687
2018	56,016
2017	15,203
Prior	123,625
Revolving Loans	1,745
Total	671,143
One- to four-family residential \| Watch
2021 YTD	0
2020	0
2019	1,364
2018	132
2017	0
Prior	270
Revolving Loans	72
Total	1,838
One- to four-family residential \| Special Mention
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
One- to four-family residential \| Classified
2021 YTD	0
2020	0
2019	136
2018	0
2017	195
Prior	1,740
Revolving Loans	89
Total	2,160
Other residential
2021 YTD	30,316
2020	59,009
2019	174,613
2018	289,348
2017	137,820
Prior	83,472
Revolving Loans	8,707
Total	783,285
Other residential \| Satisfactory
2021 YTD	30,316
2020	59,009
2019	174,613
2018	289,348
2017	137,820
Prior	80,015
Revolving Loans	8,707
Total	779,828
Other residential \| Watch
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	3,457
Revolving Loans	0
Total	3,457
Other residential \| Special Mention
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Other residential \| Classified
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Commercial business
2021 YTD	58,592
2020	26,976
2019	27,366
2018	16,937
2017	25,110
Prior	58,604
Revolving Loans	46,282
Total	259,867
Commercial business \| Satisfactory
2021 YTD	58,592
2020	26,976
2019	27,366
2018	16,937
2017	25,110
Prior	58,475
Revolving Loans	46,223
Total	259,679
Commercial business \| Watch
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	77
Revolving Loans	0
Total	77
Commercial business \| Special Mention
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Total	0
Commercial business \| Classified
2021 YTD	0
2020	0
2019	0
2018	0
2017	0
Prior	52
Revolving Loans	59
Total	$ 111

Amount of financing receivable originated more than five years prior to current fiscal year.

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