Employee Benefit Plans - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2021 USD ($)
Florida Public Utilities Company Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension plan	$ 400
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	2,100
Chesapeake Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension plan	100
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	300
Chesapeake Pension SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	200
Chesapeake Postretirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Contribution to pension plan	200
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	200
Florida Public Utilities Company Medical Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Expected Future Employer Contributions, Remainder of Fiscal Year	$ 100