Employee Benefit Plans - Summary of Benefit Obligations and Funded Status of the Plan (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation at end of year	$ 124,377,000	$ 120,241,000
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	127,127,000	163,919,000
Service cost	1,418,000	2,190,000	$ 2,500,000
Interest cost	6,304,000	4,114,000	3,416,000
Actuarial loss (gain)	2,650,000	(36,981,000)
Benefits paid	(6,425,000)	(6,115,000)
Projected benefit obligation at end of year	131,074,000	127,127,000	163,919,000
Change in fair value of plan assets:
Fair value of plan assets at beginning of year	166,906,000	202,783,000
Actual return on plan assets	22,396,000	(29,762,000)
Employer contribution	0	0	0
Benefits paid	(6,425,000)	(6,115,000)
Fair value of plan assets at end of year	182,877,000	166,906,000	202,783,000
Amounts recognized in the statement of financial position:
Funded status	51,803,000	39,779,000
Net amounts recognized as receivable pension costs in the consolidated balance sheets	51,803,000	39,779,000
Amounts recognized in accumulated other comprehensive income consist of:
Unrecognized prior service credit	(124,000)	(159,000)
Unrecognized net (gain) loss	(2,947,000)	6,548,000
Net amounts recognized in accumulated other comprehensive income (before tax)	$ (3,071,000)	$ 6,389,000
Weighted average assumptions used to determine benefit obligations:
Discount rate	5.04%	5.23%
Rate of compensation increase	3.78%	3.84%
Expected long-term return on assets	5.83%	6.82%
Farmers Capital Bank Corporation Postretirement Medical Benefit Plan [Member]
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	$ 7,119,000	$ 11,245,000
Interest cost	332,000	266,000
Actuarial loss (gain)	(316,000)	(3,881,000)
Participant contributions	332,000	320,000
Benefits paid	(857,000)	(831,000)
Projected benefit obligation at end of year	6,610,000	7,119,000	$ 11,245,000
Amounts recognized in the statement of financial position:
Funded status	6,610,000	7,119,000
Net amounts recognized as receivable pension costs in the consolidated balance sheets	6,610,000	7,119,000
Amounts recognized in accumulated other comprehensive income consist of:
Unrecognized prior service credit	(2,119,000)	(2,343,000)
Unrecognized net (gain) loss	(3,748,000)	(3,676,000)
Net amounts recognized in accumulated other comprehensive income (before tax)	$ (5,867,000)	$ (6,019,000)
Weighted average assumptions used to determine benefit obligations:
Discount rate	5.01%	5.20%