Employee Benefit Plans - Schedule of Estimated Future Benefit Payments (Detail) $ in Thousands	Dec. 31, 2020 USD ($)
Chesapeake Pension Plan
Defined Benefit Plan, Expected Future Benefit Payments, Maturity [Line Items]
2017	$ 384	[1]
2018	99	[1]
2019	981	[1]
2020	106	[1]
2021	1,007	[1]
Years 2022 through 2026	1,193	[1]
FPU Pension Plan
Defined Benefit Plan, Expected Future Benefit Payments, Maturity [Line Items]
2017	3,409	[1]
2018	3,493	[1]
2019	3,559	[1]
2020	3,601	[1]
2021	3,680	[1]
Years 2022 through 2026	18,627	[1]
Chesapeake SERP
Defined Benefit Plan, Expected Future Benefit Payments, Maturity [Line Items]
2017	151	[2]
2018	150	[2]
2019	148	[2]
2020	146	[2]
2021	158	[2]
Years 2022 through 2026	735	[2]
Chesapeake Postretirement Plan
Defined Benefit Plan, Expected Future Benefit Payments, Maturity [Line Items]
2017	68	[2]
2018	66	[2]
2019	61	[2]
2020	58	[2]
2021	55	[2]
Years 2022 through 2026	222	[2]
FPU Medical Plan
Defined Benefit Plan, Expected Future Benefit Payments, Maturity [Line Items]
2017	67	[2]
2018	67	[2]
2019	66	[2]
2020	67	[2]
2021	67	[2]
Years 2022 through 2026	$ 317	[2]

[1] The pension plan is funded; therefore, benefit payments are expected to be paid out of the plan assets.

[2] Benefit payments are expected to be paid out of our general funds.