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
		Mar. 31, 2016	Mar. 31, 2015
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)		$ (20)	$ (17)
Net loss		272	248
Recognized from accumulated other comprehensive loss	[1]	148	137
Recognized from regulatory asset		104	94
Total recognized in net periodic benefit cost		252	231
Chesapeake Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)		0	0
Net loss		104	90
Recognized from accumulated other comprehensive loss	[1]	104	90
Recognized from regulatory asset		0	0
Total recognized in net periodic benefit cost		104	90
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		128	114
Recognized from accumulated other comprehensive loss	[1]	24	22
Recognized from regulatory asset		104	92
Total recognized in net periodic benefit cost		128	114
Chesapeake Pension SERP [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)		0	2
Net loss		22	25
Recognized from accumulated other comprehensive loss	[1]	22	27
Recognized from regulatory asset		0	0
Total recognized in net periodic benefit cost		22	27
Chesapeake Postretirement Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans [Line Items]
Prior service cost (credit)		(20)	(19)
Net loss		18	17
Recognized from accumulated other comprehensive loss	[1]	(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		0	2
Recognized from accumulated other comprehensive loss	[1]	0	0
Recognized from regulatory asset		0	2
Total recognized in net periodic benefit cost		$ 0	$ 2

[1] (1) See Note 8, Accumulated Other Comprehensive Loss.