Significant Accounting Policies - Credit Losses - ASU 2016-13 $ in Thousands	6 Months Ended
	Jun. 30, 2022 USD ($) numberOfLeases	Dec. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ 1,356	$ 2,018
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	38
Accounts Receivable, Allowance for Credit Loss, Recovery	$ (700)
Number of Net Investments in Sales-Type Leases | numberOfLeases	2
Sales-type Lease, Net Investment in Lease, Allowance for Credit Loss	$ 0
Regulatory Assets, Noncurrent	301,855	314,579	$ 330,710
COVID-19 Related Costs
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Regulatory Assets, Noncurrent	13,400		$ 5,800
Residential [Member]
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	850	1,460
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	(142)
Accounts Receivable, Allowance for Credit Loss, Recovery	(468)
Commercial [Member]
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	120	178
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	52
Accounts Receivable, Allowance for Credit Loss, Recovery	(110)
Industrial [Member]
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	150	67
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	110
Accounts Receivable, Allowance for Credit Loss, Recovery	(27)
Accrued unbilled and other [Member]
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	236	$ 313
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	18
Accounts Receivable, Allowance for Credit Loss, Recovery	$ (95)