Employee Benefit Plans - Amounts Included in Regulatory Asset and Accumulated Other Comprehensive Income/Loss Recognized as Net Periodic Benefit Cost (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)	$ (17)	$ (14)
Net loss	248	66
Recognized from accumulated other comprehensive loss	137	52
Recognized from regulatory asset	94	0
Total recognized in net periodic benefit cost	231	52
Chesapeake Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)	0	0
Net loss	90	37
Recognized from accumulated other comprehensive loss	90	37
Recognized from regulatory asset	0	0
Total recognized in net periodic benefit cost	90	37
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)	0	0
Net loss	114	0
Recognized from accumulated other comprehensive loss	22	0
Recognized from regulatory asset	92	0
Total recognized in net periodic benefit cost	114	0
Chesapeake Pension SERP [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)	2	5
Net loss	25	12
Recognized from accumulated other comprehensive loss	27	17
Recognized from regulatory asset	0	0
Total recognized in net periodic benefit cost	27	17
Chesapeake Postretirement Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)	(19)	(19)
Net loss	17	17
Recognized from accumulated other comprehensive loss	(2)	(2)
Recognized from regulatory asset	0	0
Total recognized in net periodic benefit cost	(2)	(2)
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)	0	0
Net loss	2	0
Recognized from accumulated other comprehensive loss	0	0
Recognized from regulatory asset	2	0
Total recognized in net periodic benefit cost	$ 2	$ 0