LOANS AND ALLOWANCE FOR CREDIT LOSSES - Classes of loans by aging (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	$ 4,637,241	$ 4,581,381
One- to four-family residential construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	29,383	33,849
Subdivision construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	26,412	32,067
Land development
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	54,633	41,613
Commercial construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	750,818	757,690
Owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	773,082	778,533
Non-owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	123,750	124,870
Commercial real estate
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	1,503,915	1,530,663
Other residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	845,373	781,761
Commercial business
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	343,648	293,228
Industrial revenue bonds
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	12,292	12,852
Consumer auto
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	29,329	37,281
Consumer other
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	32,941	33,732
Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	111,665	123,242
30-59 Days Past Due
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	496	3,394
30-59 Days Past Due | Owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	122	2,568
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	45	100
30-59 Days Past Due | Consumer other
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	206	288
30-59 Days Past Due | Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	123	234
60-89 Days Past Due
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	340	711
60-89 Days Past Due | One- to four-family residential construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	12
60-89 Days Past Due | Owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	69	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 | Commercial real estate
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	191
60-89 Days Past Due | Consumer auto
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	3	34
60-89 Days Past Due | Consumer other
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	11	114
60-89 Days Past Due | Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	54	38
Over 90 Days Past Due
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	10,831	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	242	722
Over 90 Days Past Due | Commercial real estate
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	10,131	1,579
Over 90 Days Past Due | Commercial business
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class		586
Over 90 Days Past Due | Consumer auto
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	9	14
Over 90 Days Past Due | Consumer other
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	33	111
Over 90 Days Past Due | Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	32	274
Total Past Due
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	11,667	7,775
Total Past Due | One- to four-family residential construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	12
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	433	3,752
Total Past Due | Non-owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class		63
Total Past Due | Commercial real estate
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	10,322	1,775
Total Past Due | Commercial business
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class		594
Total Past Due | Consumer auto
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	57	148
Total Past Due | Consumer other
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	250	513
Total Past Due | Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	209	546
Current
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	4,625,574	4,573,606
Current | One- to four-family residential construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	29,371	33,849
Current | Subdivision construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	26,412	32,067
Current | Land development
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	54,249	41,229
Current | Commercial construction
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	750,818	757,690
Current | Owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	772,649	774,781
Current | Non-owner occupied one- to four-family residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	123,750	124,807
Current | Commercial real estate
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	1,493,593	1,528,888
Current | Other residential
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	845,373	781,761
Current | Commercial business
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	343,648	292,634
Current | Industrial revenue bonds
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	12,292	12,852
Current | Consumer auto
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	29,272	37,133
Current | Consumer other
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	32,691	33,219
Current | Home equity lines of credit
LOANS AND ALLOWANCE FOR CREDIT LOSSES
Financing receivables by class	$ 111,456	$ 122,696