LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES - DELINQUENT LOANS (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Aging or recorded investments in loans
Total Loans Delinquent	$ 17,826	$ 14,101
Total Loans Not Delinquent	4,118,369	3,999,933
Carrying value of loans	$ 4,136,195	$ 4,014,034
Delinquent acquired bank loans to total acquired bank loans (as a percent)	0.43%	0.35%
30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	$ 8,897	$ 7,833
Delinquent acquired bank loans to total acquired bank loans (as a percent)	0.22%	0.20%
60 - 89 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	$ 4,021	$ 2,353
Delinquent acquired bank loans to total acquired bank loans (as a percent)	0.10%	0.06%
90 + Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	$ 4,908	$ 3,915
Delinquent acquired bank loans to total acquired bank loans (as a percent)	0.12%	0.10%
Core Banking Activities
Aging or recorded investments in loans
Total Loans Delinquent	$ 11,840	$ 8,460
Total Loans Not Delinquent	4,039,389	3,927,038
Carrying value of loans	4,051,229	3,935,498
Core Banking Activities | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	4,194	4,202
Core Banking Activities | 60 - 89 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	2,987	1,280
Core Banking Activities | 90 + Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	4,659	2,978
Traditional Banking
Aging or recorded investments in loans
Total Loans Delinquent	11,840	8,460
Total Loans Not Delinquent	3,478,575	3,401,466
Carrying value of loans	3,490,415	3,409,926
Traditional Banking | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	4,194	4,202
Traditional Banking | 60 - 89 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	2,987	1,280
Traditional Banking | 90 + Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	4,659	2,978
Republic Processing Group
Aging or recorded investments in loans
Total Loans Delinquent	5,986	5,641
Total Loans Not Delinquent	78,980	72,895
Carrying value of loans	84,966	78,536
Republic Processing Group | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	4,703	3,631
Republic Processing Group | 60 - 89 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	1,034	1,073
Republic Processing Group | 90 + Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	249	937
Residential Real Estate - Owner Occupied | Traditional Banking
Aging or recorded investments in loans
Total Loans Delinquent	7,464	4,782
Total Loans Not Delinquent	905,764	916,783
Carrying value of loans	913,228	921,565
Residential Real Estate - Owner Occupied | Traditional Banking | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	2,182	2,559
Residential Real Estate - Owner Occupied | Traditional Banking | 60 - 89 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	2,161	1,166
Residential Real Estate - Owner Occupied | Traditional Banking | 90 + Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	3,121	1,057
Residential Real Estate - Owner Occupied - Correspondent | Traditional Banking
Aging or recorded investments in loans
Total Loans Not Delinquent	99,096	116,792
Carrying value of loans	99,096	116,792
Residential Real Estate - Non Owner Occupied | Traditional Banking
Aging or recorded investments in loans
Total Loans Delinquent	603	146
Total Loans Not Delinquent	231,703	204,935
Carrying value of loans	232,306	205,081
Residential Real Estate - Non Owner Occupied | Traditional Banking | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	29	47
Residential Real Estate - Non Owner Occupied | Traditional Banking | 60 - 89 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	501
Residential Real Estate - Non Owner Occupied | Traditional Banking | 90 + Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	73	99
Commercial Real Estate | Traditional Banking
Aging or recorded investments in loans
Total Loans Delinquent	1,442	1,727
Total Loans Not Delinquent	1,213,362	1,205,566
Carrying value of loans	1,214,804	1,207,293
Commercial Real Estate | Traditional Banking | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	225	398
Commercial Real Estate | Traditional Banking | 90 + Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	1,217	1,329
Construction & land development | Traditional Banking
Aging or recorded investments in loans
Total Loans Delinquent	332	67
Total Loans Not Delinquent	173,711	149,998
Carrying value of loans	174,043	150,065
Construction & land development | Traditional Banking | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	332	67
Commercial & industrial | Traditional Banking
Aging or recorded investments in loans
Total Loans Delinquent	28	15
Total Loans Not Delinquent	387,738	341,677
Carrying value of loans	387,766	341,692
Commercial & industrial | Traditional Banking | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	28	15
Lease Financing Receivables | Traditional Banking
Aging or recorded investments in loans
Total Loans Not Delinquent	15,229	16,580
Carrying value of loans	15,229	16,580
Home equity lines of credit | Traditional Banking
Aging or recorded investments in loans
Total Loans Delinquent	1,419	1,221
Total Loans Not Delinquent	331,271	346,434
Carrying value of loans	332,690	347,655
Home equity lines of credit | Traditional Banking | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	1,010	723
Home equity lines of credit | Traditional Banking | 60 - 89 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	229	50
Home equity lines of credit | Traditional Banking | 90 + Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	180	448
Consumer: Credit cards | Traditional Banking
Aging or recorded investments in loans
Total Loans Delinquent	143	74
Total Loans Not Delinquent	19,008	16,004
Carrying value of loans	19,151	16,078
Consumer: Credit cards | Traditional Banking | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	62	34
Consumer: Credit cards | Traditional Banking | 60 - 89 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	81	40
Consumer: Overdrafts | Traditional Banking
Aging or recorded investments in loans
Total Loans Delinquent	259	233
Total Loans Not Delinquent	724	741
Carrying value of loans	983	974
Consumer: Overdrafts | Traditional Banking | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	251	230
Consumer: Overdrafts | Traditional Banking | 60 - 89 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	7	3
Consumer: Overdrafts | Traditional Banking | 90 + Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	1
Consumer: Automobile loan | Traditional Banking
Aging or recorded investments in loans
Total Loans Delinquent	92	60
Total Loans Not Delinquent	62,087	65,590
Carrying value of loans	62,179	65,650
Consumer: Automobile loan | Traditional Banking | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	31	36
Consumer: Automobile loan | Traditional Banking | 90 + Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	61	24
Other consumer | Traditional Banking
Aging or recorded investments in loans
Total Loans Delinquent	58	135
Total Loans Not Delinquent	38,882	20,366
Carrying value of loans	38,940	20,501
Other consumer | Traditional Banking | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	44	93
Other consumer | Traditional Banking | 60 - 89 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	8	21
Other consumer | Traditional Banking | 90 + Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	6	21
Warehouse lines of credit | Warehouse Lending
Aging or recorded investments in loans
Total Loans Not Delinquent	560,814	525,572
Carrying value of loans	560,814	525,572
Other TRS loans | Republic Processing Group
Aging or recorded investments in loans
Total Loans Not Delinquent	292	11,648
Carrying value of loans	292	11,648
Republic Credit Solutions | Republic Processing Group
Aging or recorded investments in loans
Total Loans Delinquent	5,986	5,641
Total Loans Not Delinquent	78,688	61,247
Carrying value of loans	84,674	66,888
Republic Credit Solutions | Republic Processing Group | 30 - 59 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	4,703	3,631
Republic Credit Solutions | Republic Processing Group | 60 - 89 Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	1,034	1,073
Republic Credit Solutions | Republic Processing Group | 90 + Days Delinquent
Aging or recorded investments in loans
Total Loans Delinquent	$ 249	$ 937