Employee Benefit Plans - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Document Period End Date	Mar. 31, 2015
Expected pension and postretirement benefit costs	$ 1,150,000
Expected amortization of pre merger regulatory asset	769,000
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	17,000	17,000
Contribution to pension plan	92,000
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year	207,000
Chesapeake Postretirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	9,000	11,000
Contribution to pension plan	15,000
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year	79,000
Chesapeake Pension SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	50,000	40,000
Contribution to pension plan	33,000
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year	151,000
Consolidated [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	(381,000)
Chesapeake Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	57,000	11,000
Contribution to pension plan	104,000
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year	475,000
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Unamortized balance of regulatory asset	3,400,000		3,600,000
Defined Benefit Plan, Net Periodic Benefit Cost	(37,000)	(126,000)
Contribution to pension plan	343,000
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year	$ 1,551,000