Employee Benefit Plans - Amounts Included in Regulatory Asset and Accumulated Other Comprehensive Income/Loss Recognized as Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)	$ (17)	$ (15)	$ (34)	$ (30)
Net loss	249	67	496	132
Recognized from accumulated other comprehensive loss	138	52	276	102
Recognized from regulatory asset	94	0	186	0
Total recognized in net periodic benefit cost	232	52	462	102
Chesapeake Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)	0	0	0	0
Net loss	91	38	181	75
Recognized from accumulated other comprehensive loss	91	38	181	75
Recognized from regulatory asset	0	0	0	0
Total recognized in net periodic benefit cost	91	38	181	75
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)	0	0	0	0
Net loss	114	0	227	0
Recognized from accumulated other comprehensive loss	22	0	43	0
Recognized from regulatory asset	92	0	184	0
Total recognized in net periodic benefit cost	114	0	227	0
Chesapeake Pension SERP [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)	2	5	5	9
Net loss	25	12	50	24
Recognized from accumulated other comprehensive loss	27	17	55	33
Recognized from regulatory asset	0	0	0	0
Total recognized in net periodic benefit cost	27	17	55	33
Chesapeake Postretirement Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)	(19)	(20)	(39)	(39)
Net loss	17	17	35	33
Recognized from accumulated other comprehensive loss	(2)	(3)	(4)	(6)
Recognized from regulatory asset	0	0	0	0
Total recognized in net periodic benefit cost	(2)	(3)	(4)	(6)
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)	0	0	0	0
Net loss	2	0	3	0
Recognized from accumulated other comprehensive loss	0	0	1	0
Recognized from regulatory asset	2	0	2	0
Total recognized in net periodic benefit cost	$ 2	$ 0	$ 3	$ 0