Income Taxes - Summary of Significant Factors Impact on Difference Between Effective Tax Rate and Federal Statutory Rate (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Income Tax Disclosure [Abstract]
Federal income taxes at statutory rates	$ 2,195	$ 3,459	$ 14,948	$ 20,297
Flow through related to deduction of meters and mixed service costs	(2,401)		(19,835)
Tax effect of regulatory treatment of utility plant differences	(976)	(1,085)	(7,298)	(7,051)
State income tax expense	78	241	901	719
Settlement of equity awards		(21)	(19)	909
Other	105	(196)	(532)	(312)
Total income tax expense (benefit)	$ (999)	$ 2,398	$ (11,835)	$ 14,562
Federal income taxes at statutory rates	21.00%	21.00%	21.00%	21.00%
Flow through related to deduction of meters and mixed service costs	(23.00%)		(27.90%)
Tax effect of regulatory treatment of utility plant differences	(9.30%)	(6.60%)	(10.30%)	(7.30%)
State income tax expense	0.70%	1.50%	1.30%	0.70%
Settlement of equity awards		(0.10%)		1.00%
Other	1.00%	(1.20%)	(0.70%)	(0.30%)
Total income tax expense (benefit)	(9.60%)	14.60%	(16.60%)	15.10%