Employee Benefit Plans - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Expected pension and postretirement benefit costs			$ 1,700
Expected amortization of pre merger regulatory asset			769
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Unamortized balance of regulatory asset	$ 2,300		2,300		$ 2,900
Defined Benefit Plan, Net Periodic Benefit Cost	143	$ (37)	256	$ (112)
Contribution to pension plan	374		1,300
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year			1,600
Consolidated [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost			(917)
Chesapeake Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	77	58	232	173
Contribution to pension plan	116		390
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year			508
Chesapeake Pension SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	45	50	134	150
Contribution to pension plan	38		114
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year			151
Chesapeake Postretirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	7	9	23	28
Contribution to pension plan	23		59
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year			82
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Net Periodic Benefit Cost	14	$ 17	41	$ 50
Contribution to pension plan	$ 32		97
Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year			$ 149