Consolidated Statements Of Equity And Redeemable Noncontrolling Interests (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Noncontrolling Interests [Member]	Redeemable Noncontrolling Interests [Member]
Beginning Balance at Dec. 31, 2010		$ 827,592	$ (4,326)	$ 302,518	$ (600)	$ 46,722
Beginning Balance (in shares) at Dec. 31, 2010		57,119,723
Net income attributable to noncontrollling interests					756
Net income attributable to noncontrolling interests						2,559
Issuance of common stock through equity compensation plans (in shares)		275,057
Issuance of common stock through Employee Investment Plan (401-K), (in shares)		43,179
Issuance of common stock through Dividend Reinvestment Plan, (in shares)		177,822
Issuance of common stock		807,000
Equity compensation expense		3,635
Issuance of common stock through equity compensation plans		1,879
Issuance of common stock through Employee Investment Plan (401-K)		1,073
Issuance of common stock through Dividend Reinvestment Plan		4,299
Issuance of common stock, net of issuance costs		19,213
Equity transactions of consolidated subsidiaries		(2,503)
Other comprehensive income (loss)	(1,311)		(1,311)
Net income attributable to Avista Corporation shareholders	100,224			100,224
Cash dividends paid (common stock)				(63,737)
Total equity	1,185,875
Issuance of subsidiary noncontrolling interests	0				0	0
Deconsolidation of variable interest entity					0
Other					18
Purchase of subsidiary noncontrolling interests					0	(6,179)
Expiration of subsidiary noncontrolling interests redemption rights				0	0	0
Valuation adjustments and other noncontrolling interests activity				(2,855)		8,707
Ending Balance at Dec. 31, 2011	1,185,701	855,188	(5,637)	336,150	174	51,809
Ending Balance (in shares) at Dec. 31, 2011		58,422,781
Net income attributable to noncontrollling interests					451
Net income attributable to noncontrolling interests						139
Issuance of common stock through equity compensation plans (in shares)		245,661
Issuance of common stock through Employee Investment Plan (401-K), (in shares)		45,715
Issuance of common stock through Dividend Reinvestment Plan, (in shares)		167,448
Issuance of common stock		931,191
Equity compensation expense		5,716
Issuance of common stock through equity compensation plans		305
Issuance of common stock through Employee Investment Plan (401-K)		1,165
Issuance of common stock through Dividend Reinvestment Plan		4,226
Issuance of common stock, net of issuance costs		23,383
Equity transactions of consolidated subsidiaries		(746)
Other comprehensive income (loss)	(1,063)		(1,063)
Net income attributable to Avista Corporation shareholders	78,210			78,210
Cash dividends paid (common stock)				(68,552)
Total equity	1,277,135
Issuance of subsidiary noncontrolling interests	3,714				0	3,714
Deconsolidation of variable interest entity					(673)
Other					33
Purchase of subsidiary noncontrolling interests					(117)	(784)
Expiration of subsidiary noncontrolling interests redemption rights				23,805	17,790	(41,595)
Valuation adjustments and other noncontrolling interests activity				7,327		(8,345)
Ending Balance at Dec. 31, 2012	1,259,477	889,237	(6,700)	376,940	17,658	4,938
Ending Balance (in shares) at Dec. 31, 2012	59,812,796	59,812,796
Net income attributable to noncontrollling interests					1,066
Net income attributable to noncontrolling interests						151
Issuance of common stock through equity compensation plans (in shares)		58,002
Issuance of common stock through Employee Investment Plan (401-K), (in shares)		42,073
Issuance of common stock through Dividend Reinvestment Plan, (in shares)		163,881
Issuance of common stock		0
Equity compensation expense		6,002
Issuance of common stock through equity compensation plans		(878)
Issuance of common stock through Employee Investment Plan (401-K)		1,127
Issuance of common stock through Dividend Reinvestment Plan		4,360
Issuance of common stock, net of issuance costs		0
Equity transactions of consolidated subsidiaries		(2,855)
Other comprehensive income (loss)	881		881
Net income attributable to Avista Corporation shareholders	111,077			111,077
Cash dividends paid (common stock)				(73,276)
Total equity	1,318,267
Issuance of subsidiary noncontrolling interests	480				480	0
Deconsolidation of variable interest entity					0
Other					4,979
Purchase of subsidiary noncontrolling interests					(4,182)	(405)
Expiration of subsidiary noncontrolling interests redemption rights				0	0	0
Valuation adjustments and other noncontrolling interests activity				(7,649)		11,205
Ending Balance at Dec. 31, 2013	$ 1,298,266	$ 896,993	$ (5,819)	$ 407,092	$ 20,001	$ 15,889
Ending Balance (in shares) at Dec. 31, 2013	60,076,752	60,076,752