Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost		$ (19)	$ (19)	$ (38)	$ (38)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		230	217	458	434
Defined Benefit Plan Amounts Recognized Gain (Loss)		211	198	420	396
Recognized from accumulated other comprehensive loss	[1]	87	89	171	178
Recognized from regulatory asset		124	109	249	218
Defined Benefit Plan Actuarial Gain Loss, Net Settlement			198		396
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension plan		500
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		2,100		2,100
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		155	135	310	270
Defined Benefit Plan Amounts Recognized Gain (Loss)		155	135	310	270
Recognized from accumulated other comprehensive loss	[1]	29	26	58	52
Recognized from regulatory asset		126	109	252	218
Chesapeake Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension plan		100
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		300		300
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		60	65	120	130
Defined Benefit Plan Amounts Recognized Gain (Loss)		60	65	120	130
Recognized from accumulated other comprehensive loss	[1]	60	65	120	130
Chesapeake Pension SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension plan				100
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		200		200
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		7	5	14	10
Defined Benefit Plan Amounts Recognized Gain (Loss)		7	5	14	10
Recognized from accumulated other comprehensive loss	[1]	7	5	14	10
Defined Benefit Plan Actuarial Gain Loss, Net Settlement			5		10
Chesapeake Postretirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension plan				200
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		200		200
Amortization of prior service cost		(19)	(19)	(38)	(38)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		10	12	18	24
Defined Benefit Plan Amounts Recognized Gain (Loss)		(9)	(7)	(20)	(14)
Recognized from accumulated other comprehensive loss	[1]	(9)	$ (7)	(20)	$ (14)
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year		100		100
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		(2)		(4)
Defined Benefit Plan Amounts Recognized Gain (Loss)		(2)		(4)
Recognized from accumulated other comprehensive loss	[1]			(1)
Recognized from regulatory asset		$ (2)		$ (3)

[1] See Note 9, Stockholders' Equity.