Employee Benefit Plans - Amounts Included in Regulatory Asset and Accumulated Other Comprehensive Income/Loss Recognized as Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2022	Mar. 31, 2021
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)		$ (19)	$ (19)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		143	228
Recognized from accumulated other comprehensive loss	[1]	24	85
Recognized from regulatory asset		100	124
Defined Benefit Plan Actuarial Gain Loss, Net Settlement			209
Total recognized in net periodic benefit cost		124	209
Chesapeake Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		0	60
Recognized from accumulated other comprehensive loss	[1]	0	60
Total recognized in net periodic benefit cost		0	60
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		124	155
Recognized from accumulated other comprehensive loss	[1]	24	29
Recognized from regulatory asset		100	126
Total recognized in net periodic benefit cost		124	155
Chesapeake Pension SERP [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		7	7
Recognized from accumulated other comprehensive loss	[1]	7	7
Defined Benefit Plan Actuarial Gain Loss, Net Settlement			7
Total recognized in net periodic benefit cost		7	7
Chesapeake Postretirement Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)		(19)	(19)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		12	8
Recognized from accumulated other comprehensive loss	[1]	(7)	(11)
Total recognized in net periodic benefit cost		$ (7)	(11)
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)			(2)
Recognized from regulatory asset			(2)
Total recognized in net periodic benefit cost			$ (2)

[1] See Note 9, Stockholders' Equity.