Employee Benefit Plans (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Amortization of prior service cost	$ (20)	$ (17)
Amortization of net loss	272	248
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	14	15
Expected return on plan assets	0	0
Amortization of prior service cost	0	0
Amortization of net loss	0	2
Net periodic cost (benefit)	14	17
Amortization of pre-merger regulatory asset	2	2
Total periodic cost	16	19
Chesapeake Postretirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	11	11
Expected return on plan assets	0	0
Amortization of prior service cost	(20)	(19)
Amortization of net loss	18	17
Net periodic cost (benefit)	9	9
Amortization of pre-merger regulatory asset	0	0
Total periodic cost	9	9
Chesapeake Pension SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	23	23
Expected return on plan assets	0	0
Amortization of prior service cost	0	2
Amortization of net loss	22	25
Net periodic cost (benefit)	45	50
Amortization of pre-merger regulatory asset	0	0
Total periodic cost	45	50
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	630	626
Expected return on plan assets	(701)	(777)
Amortization of prior service cost	0	0
Amortization of net loss	128	114
Net periodic cost (benefit)	57	(37)
Amortization of pre-merger regulatory asset	191	190
Total periodic cost	248	153
Chesapeake Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	105	102
Expected return on plan assets	(131)	(135)
Amortization of prior service cost	0	0
Amortization of net loss	104	90
Net periodic cost (benefit)	78	57
Amortization of pre-merger regulatory asset	0	0
Total periodic cost	$ 78	$ 57