Employee Benefit Plans - Schedule of Funded Status of Benefit Obligation and Plan Assets (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021		Dec. 31, 2020	Dec. 31, 2019
Change in benefit obligation:
Interest cost	$ 48		$ 63	$ 74
Assumptions:
Deferred Pension Settlement Expense	600			700
Chesapeake Pension Plan
Change in benefit obligation:
Benefit obligation - beginning of year	6,146		6,214
Interest cost	141	[1]	176	375	[2]
Actuarial loss	(371)		450
Defined Benefit Plan, Benefit Obligation, Payment for Settlement	(5,884)		(612)
Benefits paid	(32)		(82)
Benefit obligation - end of year	0		6,146	6,214
Change in plan assets:
Balance, beginning of year	4,609		4,630
Actual return on plan assets	(237)		369
Employer contributions	1,544		304
Defined Benefit Plan, Plan Assets, Payment for Settlement	(5,884)		(612)
Benefits paid	(32)		(82)
Balance, end of year	0		4,609	$ 4,630
Reconciliation:
Funded status	0		(1,537)
Accrued pension cost	$ 0		$ (1,537)
Assumptions:
Discount rate	2.50%		2.25%
Expected return on plan assets	3.50%		3.50%	6.00%
FPU Pension Plan
Change in benefit obligation:
Benefit obligation - beginning of year	$ 70,366		$ 65,304
Interest cost	1,714		2,085	$ 2,452
Actuarial loss	(1,953)		6,069
Benefits paid	(3,097)		(3,092)
Benefit obligation - end of year	67,030		70,366	65,304
Change in plan assets:
Balance, beginning of year	55,966		49,703
Actual return on plan assets	4,246		6,581
Employer contributions	1,597		2,774
Benefits paid	(3,097)		(3,092)
Balance, end of year	58,712		55,966	$ 49,703
Reconciliation:
Funded status	(8,318)		(14,400)
Accrued pension cost	$ (8,318)		$ (14,400)
Assumptions:
Discount rate	2.75%		2.50%
Expected return on plan assets	6.00%		6.00%	6.50%
Chesapeake SERP
Change in benefit obligation:
Benefit obligation - beginning of year	$ 2,212		$ 2,157
Interest cost	48		63
Actuarial loss	(12)		144
Benefits paid	(152)		(152)
Benefit obligation - end of year	2,096		2,212	$ 2,157
Change in plan assets:
Employer contributions	152		152
Benefits paid	(152)		(152)
Reconciliation:
Funded status	(2,096)		(2,212)
Accrued pension cost	$ (2,096)		$ (2,212)
Assumptions:
Discount rate	2.50%		2.25%
Chesapeake Postretirement Plan
Change in benefit obligation:
Benefit obligation - beginning of year	$ 1,033		$ 1,100
Interest cost	22		26	39
Plan participants contributions	190		166
Actuarial loss	159		(34)
Benefits paid	(470)		(225)
Benefit obligation - end of year	934		1,033	1,100
Change in plan assets:
Balance, beginning of year	0		0
Employer contributions	280		59
Plan participants contributions	190		166
Benefits paid	(470)		(225)
Balance, end of year	0		0	0
Reconciliation:
Funded status	(934)		(1,033)
Accrued pension cost	$ (934)		$ (1,033)
Assumptions:
Discount rate	2.83%		2.25%
FPU Medical Plan
Change in benefit obligation:
Benefit obligation - beginning of year	$ 1,009		$ 1,224
Interest cost	24		30	48
Plan participants contributions	29		37
Actuarial loss	71		(181)
Benefits paid	(129)		(101)
Benefit obligation - end of year	1,004		1,009	1,224
Change in plan assets:
Balance, beginning of year	0		0
Employer contributions	100		64
Plan participants contributions	29		37
Benefits paid	(129)		(101)
Balance, end of year	0		0	$ 0
Reconciliation:
Funded status	(1,004)		(1,009)
Accrued pension cost	$ (1,004)		$ (1,009)
Assumptions:
Discount rate	2.51%		2.50%

[1] (2) As a result of the termination of the Chesapeake Pension Plan in 2021, we recorded $0.6 million as the final settlement expense in our consolidated statement of income which reflected a portion of the pension settlement expense that was deemed not recoverable through the regulatory process.

[2] (1) As a result of annuity purchases and lump sum payments associated with the de-risking of the Chesapeake Pension Plan, the discount rate for Chesapeake Pension Plan was re-measured which triggered settlement accounting expense in the fourth quarter of 2019. We recorded an estimated $0.7 million for the settlement expense in our consolidated statement of income which reflected a portion of the pension settlement expense that was deemed not recoverable through the regulatory process.