Revenue Recognition Disegragation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2025		Jun. 30, 2024		Jun. 30, 2025		Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Revenues	$ 192,800		$ 166,300		$ 491,500		$ 412,000
Revenue from Contract with Customer, Excluding Assessed Tax	192,800	[1]	166,300	[1]	491,500	[2]	412,000	[2]
Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenues	151,800		130,700		351,400		299,100
Revenue from Contract with Customer, Excluding Assessed Tax	151,800	[1]	130,700	[1]	351,400	[2]	299,100	[2]
Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenues	47,900		41,400		154,600		124,500
Revenue from Contract with Customer, Excluding Assessed Tax	47,900	[1]	41,400	[1]	154,600	[2]	124,500	[2]
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(6,900)	[1]	(5,800)	[1]	(14,500)	[2]	(11,600)	[2]
Other [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenues	1,000		100		500		700
Other [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenues	100				200		200
Energy Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	138,500		118,300		324,200		273,800
Energy Distribution [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	138,500		118,300		324,200		273,800
Energy Distribution [Member] | Delaware natural gas division [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	15,500		13,400		57,800		45,300
Energy Distribution [Member] | FPU Electric Distribution [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	26,200		22,500		49,400		42,500
Energy Distribution [Member] | Florida Public Utilities Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	46,600		40,000		97,900		87,900
Energy Distribution [Member] | Maryland Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	10,700	[3]	9,900	[3]	36,000	[4]	29,700	[4]
Energy Distribution [Member] | Florida City Gas | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	39,500		32,500		83,100		68,400
Energy Transmission [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	41,700		33,600		94,000		76,800
Energy Transmission [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	33,300		28,300		66,400		57,900
Energy Transmission [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	8,400		5,300		27,600		18,900
Energy Transmission [Member] | Aspire [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	8,400		5,300		27,600		18,900
Energy Transmission [Member] | Eastern Shore Gas Company [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	21,200		19,900		43,900		41,100
Energy Transmission [Member] | Peninsula Pipeline [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	11,800		8,100		21,800		16,100
Energy Transmission [Member] | Aspire Energy Express | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	300		300		700		700
Energy Generation [Member] | Eight Flags [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	4,600		4,400		9,300		9,000
Propane Delivery [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	26,500		28,000		101,200		89,600
Energy Services [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	8,400		3,700		16,600		7,100
Energy Services [Member] | Marlin Gas Services [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	7,300				14,500
Energy Services [Member] | Marlin Gas Services [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax			3,700				7,100
Energy Services [Member] | Other RNG | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,100		0		2,100		0
Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(26,900)		(21,700)		(53,800)		(44,300)
Eliminations [Member] | Regulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	(20,000)		(15,900)		(39,200)		(32,600)
Eliminations [Member] | Unregulated Energy [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0		0		(100)		(100)
Eliminations [Member] | Eliminations [Member]
Disaggregation of Revenue [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	$ (6,900)		$ (5,800)		$ (14,500)		$ (11,600)

[1] (2) Total operating revenues for the three months ended June 30, 2025 include other revenue (revenues from sources other than contracts with customers) of $1.0 million and $0.1 million for our Regulated Energy and Unregulated Energy segments, respectively, and $0.1 million for both our Regulated Energy and Unregulated Energy segments for the three months ended June 30, 2024. 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] 2) Total operating revenues for the six months ended June 30, 2025 include other revenue (revenues from sources other than contracts with customers) of $0.5 million and $0.2 million for our Regulated Energy and Unregulated Energy segments, respectively, and $0.7 million and $0.2 million for our Regulated Energy and Unregulated Energy segments, respectively, for the six months ended June 30, 2024. 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.

[3] (1) In accordance with the Maryland PSC approval of our natural gas base rate proceeding, effective April 2025, our natural gas distribution businesses in Maryland (Maryland natural gas division, Sandpiper Energy and Elkton Gas) are now consolidated for rate-making and other purposes and are reflected on a consolidated basis for all periods presented consistent with the final rate order.

[4] (1) In accordance with the Maryland PSC approval of our natural gas base rate proceeding, effective April 2025, our natural gas distribution businesses in Maryland (Maryland natural gas division, Sandpiper Energy and Elkton Gas) are now consolidated for rate-making and other purposes and are reflected on a consolidated basis for all periods presented consistent with the final rate order.