Employee Benefit Plans - Component of Net Periodic Pension Cost (Benefit) (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Components of net periodic cost:
Interest cost	$ 81	$ 50	$ 48
Chesapeake Postretirement Plan
Assumptions
Funded status	(1,100)	(600)
FPU Medical Plan
Assumptions
Funded status	(400)	(700)
Chesapeake SERP
Components of net periodic cost:
Interest cost	81	50
Actuarial (gain) loss	8	28	28
Net periodic postretirement cost	$ 89	$ 78	$ 76
Assumptions
Discount rate	5.00%	2.50%	2.25%
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ 48	$ (335)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(152)	(152)
Defined Benefit Plan, Plan Assets, Contributions by Employer	152	152
Defined Benefit Plan, Plan Assets, Benefits Paid	(152)	(152)
Accrued pension cost	$ (1,636)	$ (1,659)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.88%	5.00%
FPU Pension Plan
Components of net periodic cost:
Interest cost	$ 2,495	$ 1,781	$ 1,714
Expected return on assets	(2,670)	(3,430)	(3,306)
Actuarial (gain) loss	407	466	612
Net periodic postretirement cost	$ 232	$ (1,183)	$ (980)
Assumptions
Discount rate	5.25%	2.75%	2.50%
Expected return on plan assets	6.00%	6.00%	6.00%
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	$ 454	$ (15,713)
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(3,233)	(3,157)
Defined Benefit Plan, Plan Assets, Amount	49,432	46,203	$ 58,712
Defined Benefit Plan, Plan Assets, Contributions by Employer	0	200
Defined Benefit Plan, Plan Assets, Benefits Paid	(3,233)	(3,157)
Accrued pension cost	$ (225)	$ (3,738)
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	5.00%	5.25%