LOANS AND ALLOWANCE FOR CREDIT LOSSES - Classes of loans by aging (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	$ 4,644,650	$ 4,581,381
One- to four-family residential construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	34,508	33,849
Subdivision construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	31,424	32,067
Land development
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	48,160	41,613
Commercial construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	696,735	757,690
Owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	779,574	778,533
Non-owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	125,741	124,870
Commercial real estate
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	1,560,427	1,530,663
Other residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	885,472	781,761
Commercial business
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	287,028	293,228
Industrial revenue bonds
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	12,539	12,852
Consumer auto
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	34,289	37,281
Consumer other
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	32,924	33,732
Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	115,829	123,242
30-59 Days Past Due
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	2,119	3,394
30-59 Days Past Due | Owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	1,101	2,568
30-59 Days Past Due | Non-owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	551
30-59 Days Past Due | Commercial real estate
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class		196
30-59 Days Past Due | Commercial business
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class		8
30-59 Days Past Due | Consumer auto
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	85	100
30-59 Days Past Due | Consumer other
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	262	288
30-59 Days Past Due | Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	120	234
60-89 Days Past Due
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	213	711
60-89 Days Past Due | Owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	105	462
60-89 Days Past Due | Non-owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class		63
60-89 Days Past Due | Consumer auto
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	9	34
60-89 Days Past Due | Consumer other
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	12	114
60-89 Days Past Due | Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	87	38
Over 90 Days Past Due
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	2,982	3,670
Over 90 Days Past Due | Land development
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	384	384
Over 90 Days Past Due | Owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	625	722
Over 90 Days Past Due | Commercial real estate
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	1,526	1,579
Over 90 Days Past Due | Commercial business
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	16	586
Over 90 Days Past Due | Consumer auto
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	21	14
Over 90 Days Past Due | Consumer other
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	101	111
Over 90 Days Past Due | Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	309	274
Total Past Due
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	5,314	7,775
Total Past Due | Land development
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	384	384
Total Past Due | Owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	1,831	3,752
Total Past Due | Non-owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	551	63
Total Past Due | Commercial real estate
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	1,526	1,775
Total Past Due | Commercial business
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	16	594
Total Past Due | Consumer auto
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	115	148
Total Past Due | Consumer other
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	375	513
Total Past Due | Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	516	546
Current
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	4,639,336	4,573,606
Current | One- to four-family residential construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	34,508	33,849
Current | Subdivision construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	31,424	32,067
Current | Land development
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	47,776	41,229
Current | Commercial construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	696,735	757,690
Current | Owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	777,743	774,781
Current | Non-owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	125,190	124,807
Current | Commercial real estate
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	1,558,901	1,528,888
Current | Other residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	885,472	781,761
Current | Commercial business
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	287,012	292,634
Current | Industrial revenue bonds
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	12,539	12,852
Current | Consumer auto
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	34,174	37,133
Current | Consumer other
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	32,549	33,219
Current | Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	$ 115,313	$ 122,696