Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2022

Accounting Policies [Abstract]

Summary of Ratio of Depreciation to Average Depreciable Property and Average Service Lives for Utility Plan in Service

For utility operations, the ratio of depreciation provisions to average depreciable property was as follows for the years ended December 31:

	2022			2021			2020
Avista Utilities
Ratio of depreciation to average depreciable property		3.50	%		3.54	%		3.43	%
Alaska Electric Light and Power Company
Ratio of depreciation to average depreciable property		2.78	%		2.77	%		2.77	%

The average service lives for the following broad categories of utility plant in service are (in years):

	Avista Utilities		Alaska Electric Light and Power Company
Electric thermal/other production		26		41
Hydroelectric production		79		42
Electric transmission		50		43
Electric distribution		39		39
Natural gas distribution property		44	N/A
Other shorter-lived general plant		8		19

The gross balances of the major classifications of property, plant and equipment are detailed in the following table as of December 31 (dollars in thousands):

	2022		2021
Avista Utilities:
Electric production	$	1,593,795	$	1,494,371
Electric transmission		994,709		945,624
Electric distribution		2,236,376		2,093,937
Electric construction work-in-progress (CWIP) and other		376,981		424,733
Electric total		5,201,861		4,958,665
Natural gas underground storage		58,072		55,684
Natural gas distribution		1,452,637		1,356,477
Natural gas CWIP and other		88,264		87,852
Natural gas total		1,598,973		1,500,013
Common plant (including CWIP)		744,173		740,339
Total Avista Utilities		7,545,007		7,199,017
AEL&P:
Electric production		106,390		106,094
Electric transmission		22,856		22,691
Electric distribution		29,269		27,138
Electric CWIP and other		12,295		7,319
Electric total		170,810		163,242
Common plant		10,018		9,726
Total AEL&P		180,828		172,968
Total gross utility property		7,725,835		7,371,985
Other (1)		16,631		17,818
Total	$	7,742,466	$	7,389,803

(1)Included in other property and investments-net and other non-current assets on the Consolidated Balance Sheets. Accumulated depreciation was $2.4 million as of December 31, 2022 and $2.3 million as of December 31, 2021 for the other businesses.

Summary of Effective AFUDC Rate

The effective AFUDC rate was the following for the years ended December 31:

	2022			2021			2020
Avista Utilities		7.12	%		7.19	%		7.25	%
Alaska Electric Light and Power Company		8.08	%		8.90	%		8.04	%

Stock-Based Compensation

The Company recorded stock-based compensation expense (included in other operating expenses) and income tax benefits in the Consolidated Statements of Income of the following amounts for the years ended December 31 (dollars in thousands):

	2022			2021			2020
Stock-based compensation expense	$	7,567		$	4,713		$	5,846
Income tax benefits		1,589			990			1,228
Excess tax expenses on settled share-based employee    payments		(19	)		(909	)		(165	)

The following table summarizes the number of grants, vested and unvested shares, earned shares (based on market metrics), and other pertinent information related to the Company's stock compensation awards for the years ended December 31:

	2022		2021		2020
Restricted Shares
Shares granted during the year		115,746		62,594		45,540
Shares vested during the year		44,829		34,854		56,203
Unvested shares at end of year		157,860		96,127		71,706
Unrecognized compensation expense at end of year    (in thousands)	$	3,923	$	2,215	$	2,003
TSR Awards
TSR shares granted during the year		69,814		64,910		47,848
TSR shares vested during the year		43,730		77,174		71,299
TSR shares earned based on market metrics		48,890		58,652		—
Unvested TSR shares at end of year		130,567		107,854		122,133
Unrecognized compensation expense at end of year    (in thousands)	$	3,533	$	2,653	$	2,296
CEPS Awards
CEPS shares granted during the year		69,814		64,910		47,848
CEPS shares vested during the year		43,730		38,590		35,622
CEPS shares earned based on market metrics		—		26,627		63,763
Unvested CEPS shares at end of year		130,567		107,854		83,464
Unrecognized compensation expense at end of year    (in thousands)	$	2,471	$	1,223	$	1,090

Other Expense (Income) - Net

Other income - net consisted of the following items for the years ended December 31 (dollars in thousands):

	2022			2021			2020
Interest income	$	(1,957	)	$	(1,943	)	$	(1,952	)
Interest on regulatory deferrals		(1,914	)		(1,206	)		(1,222	)
Equity-related AFUDC		(6,704	)		(7,004	)		(6,970	)
Non-service portion of pension and other postretirement benefit    expenses		(3,037	)		1,386			6,433
Earnings on investments		(48,492	)		(21,402	)		(905	)
Other income		(613	)		(3,129	)		(201	)
Total	$	(62,717	)	$	(33,298	)	$	(4,817	)

Allowance for Doubtful Accounts

The following table presents the activity in the allowance for doubtful accounts during the years ended December 31 (dollars in thousands):

	2022			2021			2020
Allowance as of the beginning of the year	$	10,465		$	11,387		$	2,419
Additions expensed during the year (1)		149			9,279			11,280
Net deductions (2)		(4,141	)		(10,201	)		(2,312	)
Allowance as of the end of the year	$	6,473		$	10,465		$	11,387

(1)Increases in 2021 and 2020 related to COVID-19 bad debt expense in excess of the amount recovered through rates.

(2)Increase in 2021 relates to COVID forgiveness program. The Company also received support from various government agencies in 2022 in the amount of $6.1 million, which was applied to overdue customer accounts.

Estimated Retirement Costs Collected from Customers

The Company has recorded the amount of estimated retirement costs collected from customers (that do not represent legal or contractual obligations) and included them as a non-current regulatory liability on the Consolidated Balance Sheets in the following amounts as of December 31 (dollars in thousands):

	2022		2021
Regulatory liability for utility plant retirement costs	$	376,817	$	350,190

Summary of Changes in Carrying Amount of Goodwill

There were no changes in the carrying amount of goodwill during 2021 and 2022 and the balance was as follows (dollars in thousands):

	AEL&P		Accumulated Impairment Losses		Total
Balance as of December 31, 2021 and 2022	$	52,426	$	-	$	52,426

Summary of Appropriated Retained Earnings Amount Included in Retained Earnings

The appropriated retained earnings amounts included in retained earnings were as follows as of December 31 (dollars in thousands):

	2022		2021
Appropriated retained earnings	$	57,231	$	53,620