LOANS AND ALLOWANCE FOR CREDIT LOSSES - COMPOSITION OF LOANS (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2024	Dec. 31, 2023	Jun. 30, 2024	Sep. 30, 2023	Jun. 30, 2023	Dec. 31, 2022
Loans disclosures
Lease financing receivables	$ 89,653	$ 88,591
Total loans	5,296,917	5,239,861
Allowance for credit losses	(82,158)	(82,130)	$ (80,687)	$ (74,576)	$ (72,202)	$ (70,413)
Loans, net	5,214,759	5,157,731
Core Banking Activities
Loans disclosures
Total loans	5,162,059	4,958,292
Allowance for credit losses	(61,035)	(59,845)	(61,235)	(58,074)	(56,913)	(51,718)
Traditional Banking
Loans disclosures
Lease financing receivables	89,653	88,591
Total loans	4,566,896	4,618,569
Allowance for credit losses	(59,549)	(58,998)	$ (59,865)	$ (56,931)	$ (55,567)	$ (50,709)
Republic Processing Group
Loans disclosures
Total loans	134,858	281,569
Residential real estate | Residential Real Estate - Owner Occupied
Loans disclosures
Total loans	1,046,385	1,144,684
Residential real estate | Residential Real Estate - Owner Occupied | Traditional Banking
Loans disclosures
Total loans	1,046,385	1,144,684
Residential real estate | Residential Real Estate - Non Owner Occupied
Loans disclosures
Total loans	326,273	345,965
Residential real estate | Residential Real Estate - Non Owner Occupied | Traditional Banking
Loans disclosures
Total loans	326,273	345,965
Residential real estate | Home Equity
Loans disclosures
Total loans	341,204	295,133
Residential real estate | Home Equity | Traditional Banking
Loans disclosures
Total loans	341,204	295,133
Commercial real estate
Loans disclosures
Total loans	$ 1,813,303	$ 1,785,289
Percentage of Nonowner-occupied CRE loans	64.00%	63.00%
Percentage of Owner-occupied CRE loans	36.00%	37.00%
Commercial real estate | Traditional Banking
Loans disclosures
Total loans	$ 1,813,303	$ 1,785,289
Construction & land development
Loans disclosures
Total loans	247,730	217,338
Construction & land development | Traditional Banking
Loans disclosures
Total loans	247,730	217,338
Commercial & industrial | Commercial and Industrial
Loans disclosures
Total loans	437,911	464,078
Commercial & industrial | Commercial and Industrial | Traditional Banking
Loans disclosures
Total loans	437,911	464,078
Aircraft
Loans disclosures
Total loans	235,327	250,051
Aircraft | Traditional Banking
Loans disclosures
Total loans	235,327	250,051
Consumer
Loans disclosures
Total loans	29,110	27,440
Consumer | Credit Card | Traditional Banking
Loans disclosures
Total loans	16,762	16,654
Consumer | Overdrafts | Traditional Banking
Loans disclosures
Total loans	827	694
Consumer | Automobile loans | Traditional Banking
Loans disclosures
Total loans	1,340	2,664
Consumer | Other Consumer | Traditional Banking
Loans disclosures
Total loans	10,181	7,428
Warehouse lines of credit
Loans disclosures
Total loans	595,163	339,723
Warehouse lines of credit | Warehouse Lending
Loans disclosures
Total loans	595,163	339,723
Tax Refund Solution
Loans disclosures
Total loans	302	149,207
Tax Refund Solution | Refund Advances | Tax Refund Solutions
Loans disclosures
Total loans		103,115
Tax Refund Solution | Other TRS commercial and industrial loans | Tax Refund Solutions
Loans disclosures
Total loans	302	46,092
Republic Credit Solution
Loans disclosures
Total loans	134,556	132,362
Republic Credit Solution | Republic Credit Solutions
Loans disclosures
Total loans	$ 134,556	$ 132,362