Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Expected pension and postretirement benefit costs	$ 1,600
Expected amortization of pre merger regulatory asset	769
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	14	$ 17
Contribution to pension plan	38
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year	149
Chesapeake Postretirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	9	9
Contribution to pension plan	21
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year	82
Chesapeake Pension SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	45	50
Contribution to pension plan	38
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year	151
Consolidated [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	(802)
Chesapeake Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	78	57
Contribution to pension plan	104
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year	508
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Unamortized balance of regulatory asset	2,700		$ 2,800
Defined Benefit Plan, Net Periodic Benefit Cost	57	$ (37)
Contribution to pension plan	337
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year	$ 1,600