Revenue Recognition Disegragation of Revenue (Details) - USD ($)	3 Months Ended				9 Months Ended
	Sep. 30, 2024		Sep. 30, 2023		Sep. 30, 2024		Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Revenues	$ 160,138,000		$ 131,547,000		$ 572,154,000		$ 485,269,000
Revenue from Contract with Customer, Excluding Assessed Tax	160,138,000	[1]	131,547,000	[1]	572,154,000	[2]	485,269,000	[2]
Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	130,633,000	[1]	102,411,000	[1]	429,684,000	[2]	345,822,000	[2]
Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	35,567,000	[1]	34,970,000	[1]	160,089,000	[2]	158,886,000	[2]
Other Segments And Intersegments Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(6,062,000)		(5,834,000)		(17,619,000)		(19,439,000)
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(6,062,000)	[1]	(5,834,000)	[1]	(17,619,000)	[2]	(19,439,000)	[2]
Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(22,425,000)		(19,990,000)		(66,711,000)		(63,252,000)
Eliminations [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(16,300,000)		(14,099,000)		(48,906,000)		(43,626,000)
Other [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenues	200,000		100,000		900,000		900,000
Other [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenues	100,000		100,000		300,000		300,000
Revenue from Contract with Customer, Excluding Assessed Tax	(63,000)		(57,000)		(186,000)		(187,000)
Energy Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	118,017,000		89,005,000		391,750,000		306,404,000
Energy Distribution [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	118,017,000		89,005,000		391,750,000		306,404,000
Energy Distribution [Member] | Delaware natural gas division [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	9,479,000		9,793,000		54,800,000		60,809,000
Energy Distribution [Member] | Delaware natural gas division [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	9,479,000		9,793,000		54,800,000		60,809,000
Energy Distribution [Member] | FPU Electric Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	29,856,000		32,683,000		72,366,000		78,455,000
Energy Distribution [Member] | FPU Electric Distribution [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	29,856,000		32,683,000		72,366,000		78,455,000
Energy Distribution [Member] | Florida Public Utilities Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	36,941,000		38,323,000		124,814,000		125,446,000
Energy Distribution [Member] | Florida Public Utilities Company [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	36,941,000		38,323,000		124,814,000		125,446,000
Energy Distribution [Member] | Maryland Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,343,000		3,447,000		17,879,000		20,331,000
Energy Distribution [Member] | Maryland Natural Gas [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,343,000		3,447,000		17,879,000		20,331,000
Energy Distribution [Member] | Sandpiper [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,925,000		3,748,000		14,880,000		14,909,000
Energy Distribution [Member] | Sandpiper [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,925,000		3,748,000		14,880,000		14,909,000
Energy Distribution [Member] | Elkton Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,024,000				5,191,000
Energy Distribution [Member] | Elkton Gas [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,024,000		1,011,000		5,191,000		6,454,000
Energy Distribution [Member] | Florida City Gas | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	33,449,000		0		101,820,000		0
Energy Transmission [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	33,492,000		32,303,000		110,355,000		107,522,000
Energy Transmission [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	28,916,000		27,505,000		86,840,000		83,044,000
Energy Transmission [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,576,000		4,798,000		23,515,000		24,478,000
Energy Transmission [Member] | Aspire [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,576,000		4,798,000		23,515,000		24,478,000
Energy Transmission [Member] | Aspire [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,576,000		4,798,000		23,515,000		24,478,000
Energy Transmission [Member] | Eastern Shore Gas Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	19,538,000		19,228,000		60,664,000		59,530,000
Energy Transmission [Member] | Eastern Shore Gas Company [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	19,538,000		19,228,000		60,664,000		59,530,000
Energy Transmission [Member] | Peninsula Pipeline [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	9,005,000		7,904,000		25,066,000		22,408,000
Energy Transmission [Member] | Peninsula Pipeline [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	9,005,000		7,904,000		25,066,000		22,408,000
Energy Transmission [Member] | Aspire Energy Express | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	373,000		373,000		1,110,000		1,106,000
Energy Generation [Member] | Eight Flags [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,242,000		4,437,000		13,261,000		14,269,000
Energy Generation [Member] | Eight Flags [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,242,000		4,437,000		13,261,000		14,269,000
Propane Delivery [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	22,929,000		23,197,000		112,541,000		110,492,000
Propane Delivery [Member] | Florida Propane | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	22,929,000		23,197,000		112,541,000		110,492,000
Energy Services [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,883,000		2,595,000		10,958,000		9,834,000
Energy Services [Member] | Marlin Gas Services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,832,000				10,907,000
Energy Services [Member] | Marlin Gas Services [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	3,832,000		2,595,000				9,834,000
Energy Services [Member] | Other RNG | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	51,000				51,000
Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(22,470,000)		(20,035,000)		(66,847,000)		(63,388,000)
Eliminations [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(16,300,000)		(14,099,000)		(48,906,000)		(43,626,000)
Eliminations [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(63,000)		(57,000)		(186,000)		(187,000)
Eliminations [Member] | Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(6,107,000)		(5,879,000)		(17,755,000)		(19,575,000)
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	45,000		45,000		136,000		136,000
Other [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			0		0		0
Other [Member] | Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ 45,000		$ 45,000		$ 136,000		$ 136,000

[1] ) Total operating revenues for the three months ended September 30, 2024 include other revenue (revenues from sources other than contracts with customers) of $0.2 million and $0.1 million for our Regulated and Unregulated Energy segments, respectively, and $0.1 million and $0.1 million for our Regulated and Unregulated Energy segments, respectively, for the three months ended September 30, 2023. The sources of other revenues include revenue from alternative revenue programs related to revenue normalization for the Maryland division and Sandpiper Energy and late fees.

[2] (1) Total operating revenues for the nine months ended September 30, 2024 include other revenue (revenues from sources other than contracts with customers) of $0.9 million and $0.3 million for our Regulated and Unregulated Energy segments, respectively, and $0.9 million and $0.3 million for our Regulated and Unregulated Energy segments, respectively, for the nine months ended September 30, 2023. The sources of other revenues include revenue from alternative revenue programs related to revenue normalization for the Maryland division and Sandpiper Energy and late fees