Income Taxes (Tables)

3 Months Ended

Mar. 31, 2022

Income Tax Disclosure [Abstract]

Summary of Significant Factors Impact on Difference Between Effective Tax Rate and Federal Statutory Rate

The following table summarizes the significant factors impacting the difference between our effective tax rate and the federal statutory rate for the three months ended March 31 (dollars in thousands):

	2022					2021
Federal income taxes at statutory rates	$	12,753		21.0	%	$	16,838		21.0	%
Increase (decrease) in tax resulting from:
Flow through related to deduction of meters      and mixed service costs (1)		(17,434	)	(28.7	)		—		—
Tax effect of regulatory treatment of utility       plant differences (2)		(6,322	)	(10.4	)		(5,966	)	(7.4	)
State income tax expense		823		1.4			478		0.6
Settlement of equity awards		(19	)	—			930		1.2
Other		(637	)	(1.1	)		(116	)	(0.2	)
Total income tax expense (benefit)	$	(10,836	)	(17.8	)%	$	12,164		15.2	%

(1)In September and October 2021, new rates from the Company's Idaho and Washington general rate cases went into effect. While there were base rate increases approved in each of the cases, these base rate increases were offset by tax customer credits which resulted in no increase in customer billing rates. As the tax customer credits are returned to customers, this results in a decrease to income tax expense as a result of flowing through the benefits related to meters and mixed service costs. This decrease in income tax expense represents the benefits to the Company as a result of these general rate cases.

(2)In 2017, the Tax Cuts and Jobs Act (TCJA) reduced the corporate income tax rate, which resulted in a reduction to deferred income tax assets and liabilities. Prior to 2022, for depreciation-related temporary differences that are returned to customers, the Company utilized the average rate assumption method to compute the amounts returned to customers. Beginning in 2022, the Company changed to the alternative method provided for in the TCJA, to be in compliance with recently released revenue procedures and private letter rulings.