Employee Benefit Plans - Additional Information (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2020 USD ($)
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension plan	$ 0.3
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	3.2
Chesapeake Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	0.3
Chesapeake Pension SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	0.2
Chesapeake Postretirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	0.1
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	$ 0.1