Goodwill and Other Intangible Assets - Schedule of Carrying Value of Goodwill (Detail) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2021	Dec. 31, 2020
Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross		$ 19,967	$ 13,777
Finite-Lived Intangible Assets, Accumulated Amortization		6,775	5,485
Goodwill		44,708	38,731
Goodwill, Transfers	[1]	5,977
Regulated Energy
Goodwill [Line Items]
Goodwill		7,689	7,617
Goodwill, Transfers	[1]	72
Unregulated Energy
Goodwill [Line Items]
Goodwill		37,019	31,114
Goodwill, Transfers	[1]	5,905
Customer Lists [Member]
Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross	[2]	16,814	10,680
Finite-Lived Intangible Assets, Accumulated Amortization	[2]	5,125	4,269
Customer Lists [Member] | Diversified Energy
Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross		6,100
Noncompete Agreements [Member]
Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross	[2]	2,431	2,375
Finite-Lived Intangible Assets, Accumulated Amortization	[2]	1,078	768
Noncompete Agreements [Member] | Diversified Energy
Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross		100
Patents [Member]
Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross		452	452
Finite-Lived Intangible Assets, Accumulated Amortization		354	236
Other Intangible Assets [Member]
Goodwill [Line Items]
Finite-Lived Intangible Assets, Gross		270	270
Finite-Lived Intangible Assets, Accumulated Amortization		$ 218	$ 212

[1] (1)Includes goodwill from the purchase of operating assets of Diversified Energy in December 2021 and Elkton Gas in the third quarter of 2020.

[2] 1) The customer relationship and non-compete agreements amounts include $6.1 million and less than $0.1 million, respectively, as a result of the purchase of the operating assets of Diversified Energy in December 2021 and $1.3 million and $0.1 million, respectively, recorded as a result of the purchase of the operating assets of Western Natural Gas in October 2020.