TRANSACTIONS WITH RELATED PARTIES AND THEIR AFFILIATES (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) item	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Transactions with related parties and their affiliates
Rent expense under leases from related parties	$ 4,008,000	$ 3,791,000	$ 3,706,000
Total minimum lease commitments under non-cancelable operating leases
2018	6,484,000
2019	6,031,000
2020	5,461,000
2021	4,802,000
2022	3,506,000
Thereafter	6,670,000
Total	32,954,000
Loans made to executive officers and directors of Republic and their related interests
Beginning balance	37,954,000
Effect of changes in composition of related parties	(632,000)
New loans	6,787,000
Repayments	(6,957,000)
Ending balance	37,152,000	37,954,000
Affiliate
Total minimum lease commitments under non-cancelable operating leases
2018	4,199,000
2019	3,969,000
2020	3,785,000
2021	3,287,000
2022	2,390,000
Thereafter	3,919,000
Total	21,549,000
Other
Total minimum lease commitments under non-cancelable operating leases
2018	2,285,000
2019	2,062,000
2020	1,676,000
2021	1,515,000
2022	1,116,000
Thereafter	2,751,000
Total	11,405,000
Office Space Lease Company
Transactions with related parties and their affiliates
Rent expense under leases from related parties	16,000	15,000	15,000
Local law firm
Total minimum lease commitments under non-cancelable operating leases
Related party transactions incurred by the Company	$ 237,000	183,000	183,000
Consulting Firms and Local Chamber of Commerce
Total minimum lease commitments under non-cancelable operating leases
Number of consulting firms | item	2
Related party transactions incurred by the Company	$ 106,000	122,000	101,000
Accounting firm
Total minimum lease commitments under non-cancelable operating leases
Related party transactions incurred by the Company	1,000	1,000	$ 2,000
Executive officers, directors and affiliates
Loans made to executive officers and directors of Republic and their related interests
Deposits from executive officers, directors, and their affiliates	86,000,000	81,000,000
Bernard M. Trager | RB&T
Loans made to executive officers and directors of Republic and their related interests
Total aggregate annual premiums paid to date on the insurance policies held in the trust	690,000
Cash surrender value of the policies	2,000,000	2,000,000
Repayments of indebtedness due from beneficiaries, per terms of trust	690,000
Net death benefit	$ 3,000,000	$ 3,000,000