Fair Value (Tables)

12 Months Ended

Dec. 31, 2014

Fair Value Disclosures [Abstract]

Fair Value Inputs, Liabilities, Quantitative Information [Table Text Block]

The following table presents the quantitative information which was used to estimate the fair values of the Level 3 assets and liabilities above as of December 31, 2014 (dollars in thousands):

	Fair Value (Net) at
	December 31, 2014			Valuation Technique	Unobservable Input	Range
Power exchange agreement	$	(23,299	)	Surrogate facility pricing	O&M charges	$30.66-$55.56/MWh (1)
					Escalation factor	3% - 2015 to 2019
					Transaction volumes	184,077 - 397,116 MWhs
Power option agreement	(424		)	Black-Scholes- Merton	Strike price	$41.20/MWh - 2015
						$64.09/MWh - 2019
					Delivery volumes	157,517 - 287,147 MWhs
					Volatility rates	0.20 (2)
Natural gas exchange agreement	(35		)	Internally derived weighted average cost of gas	Forward purchase prices	$2.32 - $2.57/mmBTU
					Forward sales prices	$2.56 - $3.53/mmBTU
					Purchase volumes	280,000 - 310,000 mmBTUs
					Sales volumes	279,990 - 365,118 mmBTUs

(1) The average O&M charges for the delivery year beginning in November 2014 were $42.90 per MWh. For ratemaking purposes the average O&M charges to be included for recovery in retail rates vary slightly between regulatory jurisdictions. The average O&M charges for the delivery year beginning in 2014 were $43.11 for Washington and $42.90 for Idaho.

(2) The estimated volatility rate of 0.20 is compared to actual quoted volatility rates of 0.45 for 2015 to 0.21 in December2017.

Carrying Value and Estimated Fair Value of Financial Instruments

	2014				2013
	Carrying Value		Estimated Fair Value		Carrying Value		Estimated Fair Value
Long-term debt (Level 2)	$	951,000	$	1,118,972	$	951,000	$	1,054,512
Long-term debt (Level 3)	492,000		527,663		342,000		329,581
Snettisham capital lease obligation (Level 3)	69,955		79,290		—		—
Nonrecourse long-term debt (Level 3)	1,431		1,440		17,838		18,636
Long-term debt to affiliated trusts (Level 3)	51,547		38,582		51,547		37,114

Fair Value of Assets And Liabilities Measured on Recurring Basis

	Level 1		Level 2		Level 3		Counterparty and Cash Collateral Netting (1)			Total
December 31, 2014
Assets:
Energy commodity derivatives	$	—	$	96,729	$	—	$	(95,204	)	$	1,525
Level 3 energy commodity derivatives:
Natural gas exchange agreements	—		—		1,349		(1,349		)	—
Foreign currency derivatives	—		1		—		(1		)	—
Interest rate swaps	—		966		—		(506		)	460
Funds held in trust account of Spokane Energy	1,600		—		—		—			1,600
Deferred compensation assets:
Fixed income securities (2)	1,793		—		—		—			1,793
Equity securities (2)	6,074		—		—		—			6,074
Total	$	9,467	$	97,696	$	1,349	$	(97,060	)	$	11,452
Liabilities:
Energy commodity derivatives	$	—	$	127,094	$	—	$	(110,714	)	$	16,380
Level 3 energy commodity derivatives:
Natural gas exchange agreement	—		—		1,384		(1,349		)	35
Power exchange agreement	—		—		23,299		—			23,299
Power option agreement	—		—		424		—			424
Interest rate swaps	—		77,568		—		(29,386		)	48,182
Foreign currency derivatives	—		21		—		(1		)	20
Total	$	—	$	204,683	$	25,107	$	(141,450	)	$	88,340

	Level 1		Level 2		Level 3		Counterparty and Cash Collateral Netting (1)			Total
December 31, 2013
Assets:
Energy commodity derivatives	$	—	$	55,243	$	—	$	(51,367	)	$	3,876
Level 3 energy commodity derivatives:
Power exchange agreement	—		—		339		(339		)	—
Foreign currency derivatives	—		7		—		(6		)	1
Interest rate swaps	—		33,543		—		—			33,543
Investments and funds held for clients:
Money market funds	11,180		—		—		—			11,180
Securities available for sale:
U.S. government agency	—		61,078		—		—			61,078
Municipal	—		3,518		—		—			3,518
Corporate fixed income – financial	—		3,000		—		—			3,000
Corporate fixed income – industrial	—		765		—		—			765
Certificate of deposits	—		1,000		—		—			1,000
Funds held in trust account of Spokane Energy	1,600		—		—		—			1,600
Deferred compensation assets:
Fixed income securities (2)	1,960		—		—		—			1,960
Equity securities (2)	6,470		—		—		—			6,470
Total	$	21,210	$	158,154	$	339	$	(51,712	)	$	127,991
Liabilities:
Energy commodity derivatives	$	—	$	72,895	$	—	$	(60,099	)	$	12,796
Level 3 energy commodity derivatives:
Natural gas exchange agreement	—		—		1,219		—			1,219
Power exchange agreement	—		—		14,780		(339		)	14,441
Power option agreement	—		—		775		—			775
Foreign currency derivatives	—		6		—		(6		)	—
Total	$	—	$	72,901	$	16,774	$	(60,444	)	$	29,231

(1) The Company is permitted to net derivative assets and derivative liabilities with the same counterparty when a legally enforceable master netting agreement exists. In addition, the Company nets derivative assets and derivative liabilities against any payables and receivables for cash collateral held or placed with these same counterparties.

(2) These assets are trading securities and are included in other property and investments-net on the Consolidated Balance Sheets.

Reconciliation for All Assets Measured At Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3)

	Natural Gas Exchange Agreement			Power Exchange Agreement			Power Option Agreement			Total
Year ended December 31, 2014:
Balance as of January 1, 2014	$	(1,219	)	$	(14,441	)	$	(775	)	$	(16,435	)
Total gains or losses (realized/unrealized):
Included in net income	—			—			—			—
Included in other comprehensive income	—			—			—			—
Included in regulatory assets/liabilities (1)	3,873			(10,002		)	351			(5,778		)
Purchases	—			—			—			—
Issuance	—			—			—			—
Settlements	(2,689		)	1,144			—			(1,545		)
Transfers to/from other categories	—			—			—			—
Ending balance as of December 31, 2014	$	(35	)	$	(23,299	)	$	(424	)	$	(23,758	)
Year ended December 31, 2013:
Balance as of January 1, 2013	$	(2,379	)	$	(18,692	)	$	(1,480	)	$	(22,551	)
Total gains or losses (realized/unrealized):
Included in net income	—			—			—			—
Included in other comprehensive income	—			—			—			—
Included in regulatory assets/liabilities (1)	2,298			1,017			705			4,020
Purchases	—			—			—			—
Issuance	—			—			—			—
Settlements	(1,138		)	3,234			—			2,096
Transfers from other categories	—			—			—			—
Ending balance as of December 31, 2013	$	(1,219	)	$	(14,441	)	$	(775	)	$	(16,435	)

Year ended December 31, 2012:
Balance as of January 1, 2012	$	(1,688	)	$	(9,910	)	$	(1,260	)	$	(12,858	)
Total gains or losses (realized/unrealized):
Included in net income	—			—			—			—
Included in other comprehensive income	—			—			—			—
Included in regulatory assets/liabilities (1)	343			(15,236		)	(220		)	(15,113		)
Purchases	—			—			—			—
Issuance	—			—			—			—
Settlements	(1,034		)	6,454			—			5,420
Transfers from other categories	—			—			—			—
Ending balance as of December 31, 2012	$	(2,379	)	$	(18,692	)	$	(1,480	)	$	(22,551	)

(1) The UTC and the IPUC issued accounting orders authorizing Avista Corp. to offset commodity derivative assets or liabilities with a regulatory asset or liability. This accounting treatment is intended to defer the recognition of mark-to-market gains and losses on energy commodity transactions until the period of delivery. The orders provide for Avista Corp. to not recognize the unrealized gain or loss on utility derivative commodity instruments in the Consolidated Statements of Income. Realized gains or losses are recognized in the period of delivery, subject to approval for recovery through retail rates. Realized gains and losses, subject to regulatory approval, result in adjustments to retail rates through purchased gas cost adjustments, the ERM in Washington, the PCA mechanism in Idaho, and periodic general rates cases.