Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Purchase Price Allocation
Purchase price allocation, gross		$ 1,500,000
Purchase price allocation, property, plant and equipment, estimated useful lIfe		40 years
Purchase price allocation, depreciation		$ 35,000
Purchase price allocation, remaining allocation		500,000
Schedule of Equity Method Investments [Line Items]
Proceeds from Equity Method Investment, Distribution		0	$ 4,908	$ 3,250
Contributions to unconsolidated affiliates	$ 12,300	0	12,250	0
Capitalized Interest Costs, Including Allowance for Funds Used During Construction [Abstract]
Allowance for funds used during construction, borrowed		7,700	10,500	29,200
Allowance for funds used during construction, equity		14,900	$ 28,800	$ 87,100
Inventory Disclosure [Abstract]
Gas in storage, LIFO		$ 0
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		108 years
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract		15 years
Gathering facilities | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates		0.00%	0.00%	1.35%
Gathering facilities | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates		1.00%	1.00%	2.50%
Storage facilities | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates		1.86%	1.86%	2.10%
Storage facilities | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates		2.05%	2.05%	2.25%
Onshore transmission facilities | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates		2.50%	2.50%	2.61%
Onshore transmission facilities | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates		7.13%	7.13%	5.00%
Offshore transmission facilities | Minimum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates		1.25%	1.25%	1.20%
Offshore transmission facilities | Maximum [Member]
Public Utility, Property, Plant and Equipment [Line Items]
Depreciation rates		1.25%	1.25%	1.20%
Pine Needle LNG Company LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage			35.00%
Cardinal Pipeline Company LLC [Member]
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage			45.00%