Employee Benefit Plans - Employee Benefit Plans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Document Period End Date	Mar. 31, 2015
Amortization of prior service cost	$ (17)	$ (14)
Amortization of net loss	248	66
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	15	17
Expected return on plan assets	0	0
Amortization of prior service cost	0	0
Amortization of net loss	2	0
Net periodic cost (benefit)	17	17
Amortization of pre-merger regulatory asset	2	2
Total periodic cost	19	19
Chesapeake Postretirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	11	13
Expected return on plan assets	0	0
Amortization of prior service cost	(19)	(19)
Amortization of net loss	17	17
Net periodic cost (benefit)	9	11
Amortization of pre-merger regulatory asset	0	0
Total periodic cost	9	11
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	2	5
Amortization of net loss	25	12
Net periodic cost (benefit)	50	40
Amortization of pre-merger regulatory asset	0	0
Total periodic cost	50	40
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	626	647
Expected return on plan assets	(777)	(773)
Amortization of prior service cost	0	0
Amortization of net loss	114	0
Net periodic cost (benefit)	(37)	(126)
Amortization of pre-merger regulatory asset	190	190
Total periodic cost	153	64
Chesapeake Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost	102	107
Expected return on plan assets	(135)	(133)
Amortization of prior service cost	0	0
Amortization of net loss	90	37
Net periodic cost (benefit)	57	11
Amortization of pre-merger regulatory asset	0	0
Total periodic cost	$ 57	$ 11