LOANS AND ALLOWANCE FOR CREDIT LOSSES - Schedule of Accounts, Notes, Loans and Financing Receivable (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Loans Receivable weighted average interest rate	4.30%	4.29%
Allowance for credit losses
Loans Receivable	$ (67,702)	$ (55,743)
Undisbursed portion of loans in process
Loans Receivable	(851,768)	(863,722)
Deferred loan fees and gains, net
Loans Receivable	(10,907)	(9,260)
Loans Receivable
Loans Receivable	4,285,737	4,296,804
Commercial construction
Loans Receivable	1,206,687	1,212,837
Commercial Real Estate
Loans Receivable	1,588,771	1,553,677
Industrial revenue bonds
Loans Receivable	14,559	14,003
Consumer auto
Loans Receivable	73,651	86,173
Home Equity Line of Credit
Loans Receivable	113,794	114,689
Loans Receivable, Gross
Loans Receivable	5,216,114	5,225,529
Land development
Loans Receivable	54,590	54,010
One- to four-family residential construction
Loans Receivable	48,161	42,793
Subdivision construction
Loans Receivable	7,297	30,894
Owner occupied one- to four-family residential
Loans Receivable	510,343	470,436
Non-owner occupied one- to four-family residential
Loans Receivable	130,609	114,569
Other residential
Loans Receivable	1,055,395	1,021,145
Commercial business
Loans Receivable	372,533	370,898
Consumer
Loans Receivable	$ 39,724	40,762
Acquired Loans Net of Discount
Loans Receivable		$ 98,643