Significant Accounting Policies - Credit Losses - ASU 2016-13 $ in Thousands	3 Months Ended
	Mar. 31, 2022 USD ($) numberOfLeases	Dec. 31, 2021 USD ($)	Mar. 31, 2021 USD ($)
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	$ 2,488	$ 2,018
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	616
Accounts Receivable, Allowance for Credit Loss, Recovery	$ (146)
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	297,546	314,579	$ 338,692
COVID-19 Related Costs
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Regulatory Assets, Noncurrent	11,200		$ 5,000
Residential [Member]
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	1,917	1,460
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	479
Accounts Receivable, Allowance for Credit Loss, Recovery	(22)
Commercial [Member]
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	304	178
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	137
Accounts Receivable, Allowance for Credit Loss, Recovery	(11)
Industrial [Member]
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	50	67
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	9
Accounts Receivable, Allowance for Credit Loss, Recovery	(26)
Accrued unbilled and other [Member]
Accounts Receivable, Noncurrent, Credit Quality Indicator [Line Items]
Accounts Receivable, Allowance for Credit Loss	217	$ 313
Accounts Receivable, Allowance for Credit Loss, Period Increase (Decrease)	(9)
Accounts Receivable, Allowance for Credit Loss, Recovery	$ (87)