Employee Benefit Plans (Detail) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2019	Mar. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost		$ (19)	$ (19)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		268	237
Chesapeake Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost		105	97
Expected return on plan assets		(127)	(138)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		101	88
Net periodic cost (benefit)	[1]	79	47
Total periodic cost		79	47
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost		615	592
Expected return on plan assets		(693)	(774)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		129	109
Net periodic cost (benefit)	[1]	51	(73)
Amortization of pre-merger regulatory asset		190	191
Total periodic cost		241	118
Chesapeake Pension SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost		21	21
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		26	25
Net periodic cost (benefit)	[1]	47	46
Total periodic cost		47	46
Chesapeake Postretirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost		10	10
Amortization of prior service cost		(19)	(19)
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)		12	15
Net periodic cost (benefit)	[1]	3	6
Total periodic cost		3	6
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost		12	12
Net periodic cost (benefit)	[1]	12	12
Amortization of pre-merger regulatory asset		2	2
Total periodic cost		$ 14	$ 14

[1] See Note 8, Stockholder's Equity.