Leases (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) Lease	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Finance Leases [Abstract]
Number of finance leases | Lease	1
Finance lease cost [Abstract]
Amortization of right-of-use assets - finance leases	$ 50	$ 52
Interest on lease liabilities - finance leases	53	54
Total finance lease cost	103	106
Short-term lease cost	294	306
Operating lease cost	1,769	1,773
Sublease income	253	257
Total lease cost	1,913	1,928
Supplemental Cash Flow Information Related to CTBI's Operating and Finance Lease [Abstract]
Finance lease - operating cash flows	53	54
Finance lease - financing cash flows	15	14	$ (0)
Operating lease - operating cash flows (fixed payments)	1,682	1,665
Operating lease - operating cash flows (liability reduction)	1,198	0
New right-of-use assets - operating leases	$ 0	$ 9
Weighted average lease term - financing leases	25 years 7 days	26 years 7 days
Weighted average lease term - operating leases	13 years 5 months 15 days	13 years 10 months 2 days
Weighted average discount rate - financing leases	3.70%	3.70%
Weighted average discount rate - operating leases	3.43%	3.45%
Maturities of Operating Lease Liabilities [Abstract]
2021	$ 1,717
2022	1,703
2023	1,626
2024	1,313
2025	1,121
Thereafter	8,528
Total lease payments	16,008
Less imputed interest	(3,477)
Total	12,531	$ 13,729
Maturities of Finance Lease Liabilities [Abstract]
2021	75
2022	75
2023	75
2024	75
2025	75
Thereafter	1,913
Total lease payments	2,288
Less imputed interest	(847)
Total	$ 1,441	$ 1,456
Minimum [Member]
Operating Leases [Abstract]
Remaining lease terms	1 year
Maximum [Member]
Operating Leases [Abstract]
Remaining lease terms	45 years
Term of lease renewal	5 years