Employee Benefit Plans (Detail) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost		$ (19)	$ (19)	$ (38)	$ (39)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		217	268	434	537
Defined Benefit Plan Amounts Recognized Gain (Loss)		198	249	396	498
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	[1]	89	144	178	289
Defined Benefit Plan Amounts Recognized From Regulatory Asset		109	105	218	209
Chesapeake Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer				200
Interest cost		46	104	92	209
Expected return on plan assets		(42)	(127)	(84)	(254)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		65	101	130	203
Net periodic cost (benefit)	[1]	69	78	138	158
Total periodic cost		69	78	138	158
Defined Benefit Plan Amounts Recognized Gain (Loss)		65	101	130	203
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	[1]	65	101	130	203
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer		1,800		2,100
Interest cost		518	615	1,036	1,230
Expected return on plan assets		(745)	(693)	(1,490)	(1,386)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		135	129	270	258
Net periodic cost (benefit)	[1]	(92)	51	(184)	102
Amortization of pre-merger regulatory asset		0	191	0	381
Total periodic cost		(92)	242	(184)	483
Defined Benefit Plan Amounts Recognized Gain (Loss)		135	129	270	258
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	[1]	26	24	52	49
Defined Benefit Plan Amounts Recognized From Regulatory Asset		109	105	218	209
Chesapeake Pension SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Contributions by Employer				100
Interest cost		16	21	32	42
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		5	26	10	52
Net periodic cost (benefit)	[1]	21	47	42	94
Total periodic cost		21	47	42	94
Defined Benefit Plan Amounts Recognized Gain (Loss)		5	26	10	52
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	[1]	5	26	10	52
Chesapeake Postretirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost		8	9	16	19
Amortization of prior service cost		(19)	(19)	(38)	(39)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		12	12	24	24
Net periodic cost (benefit)	[1]	1	2	2	4
Total periodic cost		1	2	2	4
Defined Benefit Plan Amounts Recognized Gain (Loss)		(7)	(7)	(14)	(15)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax	[1]	(7)	(7)	(14)	(15)
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost		10	12	20	24
Net periodic cost (benefit)	[1]	10	12	20	24
Amortization of pre-merger regulatory asset		2	2	4	4
Total periodic cost		$ 12	$ 14	$ 24	$ 28

[1] See Note 9, Stockholder's Equity.