Summary Of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Accounting Policies [Abstract]

Appropriated Retained Earnings [Table Text Block]

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

	2015		2014
Appropriated retained earnings	$	21,030	$	14,270

Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]

Accumulated other comprehensive loss, net of tax, consisted of the following as of December 31 (dollars in thousands):

	2015		2014
Unfunded benefit obligation for pensions and other postretirement benefit plans - net of taxes of $3,580 and $4,247, respectively	$	6,650	$	7,888

Schedule of Goodwill [Table Text Block]

The changes in the carrying amount of goodwill are as follows (dollars in thousands):

	Ecova			AEL&P			Other		Accumulated Impairment Losses			Total
Balance as of January 1, 2014	$	71,011		$	—		$	12,979	$	(7,733	)	$	76,257
Adjustments	112			—			—		—			112
Goodwill sold during the year	(71,123		)	—			—		—			(71,123		)
Goodwill acquired during the year	—			52,730			—		—			52,730
Balance as of the December 31, 2014	—			52,730			12,979		(7,733		)	57,976
Adjustments	—			(304		)	—		—			(304		)
Balance as of the December 31, 2015	$	—		$	52,426		$	12,979	$	(7,733	)	$	57,672

Regulatory Liability For Utility Plant Retirement Costs [Table Text Block]

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 regulatory liability on the Consolidated Balance Sheets in the following amounts as of December 31 (dollars in thousands):

	2015		2014
Regulatory liability for utility plant retirement costs	$	261,594	$	254,140

Schedule of Inventory, Current [Table Text Block]

Inventories of materials and supplies, fuel stock and stored natural gas are recorded at average cost for our regulated operations and the lower of cost or market for our non-regulated operations and consisted of the following as of December 31 (dollars in thousands):

	2015		2014
Materials and supplies	$	37,101	$	32,483
Fuel stock	4,273		5,142
Stored natural gas	12,774		28,731
Total	$	54,148	$	66,356

Allowance for Credit Losses on Financing Receivables [Table Text Block]

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

	2015			2014			2013
Allowance as of the beginning of the year	$	4,888		$	44,309		$	44,155
Additions expensed during the year	5,802			5,296			5,099
Net deductions (1)	(6,160		)	(44,717		)	(4,945		)
Allowance as of the end of the year	$	4,530		$	4,888		$	44,309

(1) During the second quarter of 2014, the Company received $15.0 million in gross proceeds related to the settlement of its California wholesale power markets litigation. The gross proceeds effectively settled all outstanding receivables and payables at Avista Energy (which had been fully reserved against since 2001). As a result of the settlement, the Company reversed $15.0 million of the allowance, which was recorded as a reduction to non-utility other operating expenses on the Consolidated Statements of Income, and the remainder of the receivables, payables and allowance of $24.5 million were removed from the Consolidated Balance Sheets (and had no effect on net income).

Schedule of Other Nonoperating Income (Expense) [Table Text Block]

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

	2015			2014		2013
Interest income	$	653		$	987	$	754
Interest on regulatory deferrals	48			220		126
Equity-related AFUDC	8,331			8,808		6,066
Net gain (loss) on investments	(637		)	276		(3,378		)
Other income	905			1,055		1,599
Total	$	9,300		$	11,346	$	5,167

Schedule of Share-based Compensation, Activity [Table Text Block]

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:

	2015			2014			2013
Restricted Shares
Shares granted during the year	58,302			62,075			44,556
Shares vested during the year	(60,379		)	(52,899		)	(55,456		)
Unvested shares at end of year	106,091			112,042			104,416
Unrecognized compensation expense at end of year (in thousands)	$	1,705		$	1,349		$	1,199
TSR Awards
TSR shares granted during the year	116,435			117,550			175,000
TSR shares vested during the year	(171,334		)	(167,584		)	(176,718		)
TSR shares earned based on market metrics	222,734			97,199			—
Unvested TSR shares at end of year	223,697			287,834			344,684
Unrecognized compensation expense (in thousands)	$	3,219		$	2,833		$	3,651
CEPS Awards
CEPS shares granted during the year	58,259			59,025			—
Unvested CEPS shares at end of year	111,887			58,017			—
Unrecognized compensation expense (in thousands)	$	1,840		$	1,577		$	—

Schedule of Compensation Cost for Share-based Payment Arrangements, Allocation of Share-based Compensation Costs by Plan [Table Text Block]

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):

	2015		2014		2013
Stock-based compensation expense	$	6,914	$	6,007	$	5,037
Income tax benefits	2,420		2,102		1,763

Effective Rate On Allowance For Funds Used During Construction [Table Text Block]

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

	2015		2014		2013
Avista Utilities
Effective AFUDC rate	7.32	%	7.64	%	7.64	%
Alaska Electric Light and Power Company
Effective AFUDC rate	9.31	%	10.37	%	N/A

Schedule Of Utilities Operating Revenue Expense Taxes [Table Text Block]

Utility related taxes collected from customers (primarily state excise taxes and city utility taxes) are recorded as operating revenue and expense and totaled the following amounts for the years ended December 31 (dollars in thousands):

	2015		2014		2013
Utility taxes	$	59,173	$	58,250	$	55,565

Ratio Of Depreciation To Average Depreciable Property [Table Text Block]

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

	2015		2014		2013
Avista Utilities
Ratio of depreciation to average depreciable property	3.09	%	2.97	%	2.90	%
Alaska Electric Light and Power Company
Ratio of depreciation to average depreciable property	2.42	%	2.43	%	N/A

Unbilled Accounts Receivable [Table Text Block]

Accounts receivable includes unbilled energy revenues of the following amounts as of December 31 (dollars in thousands):

	2015		2014
Unbilled accounts receivable	$	62,003	$	80,718

Schedule of Property Plant and Equipment Useful Lives [Table Text Block]

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	40	36
Hydroelectric production	79	45
Electric transmission	57	39
Electric distribution	36	38
Natural gas distribution property	45	N/A

Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]

The following table details the reclassifications out of accumulated other comprehensive loss by component for the years ended December 31 (dollars in thousands):

	Amounts Reclassified from Accumulated Other Comprehensive Loss
Details about Accumulated Other Comprehensive Loss Components	2015			2014			Affected Line Item in Statement of Income
Realized gains on investment securities	$	—		$	3		(a)
Realized losses on investment securities	—			(735		)	(a)
	—			(732		)	Total before tax
	—			272			Tax benefit (a)
	$	—		$	(460	)	Net of tax
Amortization of defined benefit pension items
Amortization of net prior service cost	$	(31	)	$	1,094		(b)
Amortization of net loss	(2,623		)	83,301			(b)
Adjustment due to effects of regulation	749			(78,773		)	(b)
	(1,905		)	5,622			Total before tax
	667			(1,967		)	Tax expense (benefit)
	$	(1,238	)	$	3,655		Net of tax

(a) These amounts were included as part of net income from discontinued operations for all periods presented (see Note 5 for additional details).

(b) These accumulated other comprehensive loss components are included in the computation of net periodic pension cost (see Note 10 for additional details).