Rates and Other Regulatory Activities - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) Dekatherm mi	Dec. 31, 2021 USD ($)
Rates and Other Regulatory Activities [Line Items]
COVID-19 Regulatory Asset	$ 2,000	$ 2,300
Florida Public Utilities Company [Member]
Rates and Other Regulatory Activities [Line Items]
COVID-19 Settlement Amount	2,100
Delaware natural gas division [Member]
Rates and Other Regulatory Activities [Line Items]
Regulatory Liabilities	12,551	12,591
Maryland Division [Member]
Rates and Other Regulatory Activities [Line Items]
Regulatory Liabilities	3,806	3,840
Sandpiper [Member]
Rates and Other Regulatory Activities [Line Items]
Regulatory Liabilities	3,641	3,656
Central Florida Gas Division [Member]
Rates and Other Regulatory Activities [Line Items]
Regulatory Liabilities	7,986	8,032
Florida Public Utilities Company [Member]
Rates and Other Regulatory Activities [Line Items]
Regulatory Liabilities	19,086	19,189
Fort Meade and Indiantown Divisions [Member]
Rates and Other Regulatory Activities [Line Items]
Regulatory Liabilities	268	271
FPU electric division [Member]
Rates and Other Regulatory Activities [Line Items]
Regulatory Liabilities	5,176	5,237
Eastern Shore Gas Company [Member]
Rates and Other Regulatory Activities [Line Items]
Regulatory Liabilities	34,190	34,190
Elkton Gas [Member]
Rates and Other Regulatory Activities [Line Items]
Regulatory Liabilities	$ 1,091	$ 1,091
Beachside Expansion | Peninsula Pipeline Company [Member]
Rates and Other Regulatory Activities [Line Items]
Number of Mainline Pipeline Miles | mi	11.3
Additional Firm Natural Gas Transportation Deliverability | Dekatherm	10,176
Winter Haven Expansion | Peninsula Pipeline Company [Member]
Rates and Other Regulatory Activities [Line Items]
Additional Firm Natural Gas Transportation Deliverability | Dekatherm	6,800