Summary of Consolidation and Significant Accounting Policy (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2020 USD ($) mi²	Jun. 30, 2020 USD ($) mi²	Dec. 31, 2019 USD ($)	Jun. 30, 2019 USD ($)
Summary of Consolidation Policy
Allowance for Credit Losses, Beginning Balance			$ 8,294
Provision for Credit Loss		$ 9,762
Receivables Charged-Off	$ (7,157)
Allowance for Credit Loss, Ending Balance	$ 10,899	$ 10,899
Subsidiaries [Member]
Summary of Consolidation Policy
Area of Service Territory (in sqmi) | mi²	6,000	6,000
Subsidiaries [Member] | Tacoma LNG [Member]
Summary of Consolidation Policy
Jointly Owned Non-Utility Plant Share	43.00%	43.00%
Construction in Progress, Gross	$ 185,100	$ 185,100		$ 162,800
Puget LNG [Member]
Summary of Consolidation Policy
Jointly Owned Non-Utility Plant Share	57.00%	57.00%
Construction in Progress, Gross	$ 224,500	$ 224,500		$ 199,900
Puget LNG [Member] | Non-Utility Expense And Other [Member]
Summary of Consolidation Policy
Operating Costs and Expenses		$ 700