Condensed Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Operating Revenues:
Utility revenues	$ 405,460	$ 437,697
Non-utility revenues	46,797	38,889
Total operating revenues	452,257	476,586
Utility operating expenses:
Resource costs	211,012	248,121
Other operating expenses	63,357	59,682
Depreciation and amortization	27,318	25,852
Taxes other than income taxes	25,142	24,993
Non-utility operating expenses:
Other operating expenses	43,702	31,246
Depreciation and amortization	3,004	1,867
Total operating expenses	373,535	391,761
Income from operations	78,722	84,825
Interest expense	19,137	18,440
Interest expense to affiliated trusts	140	151
Capitalized interest	(525)	(438)
Other expense-net	619	632
Income before income taxes	59,351	66,040
Income tax expense	21,138	23,637
Net income	38,213	42,403
Net loss (income) attributable to noncontrolling interests	175	(485)
Net income attributable to Avista Corporation	$ 38,388	$ 41,918
Weighted-average common shares outstanding (thousands), basic	58,581	57,342
Weighted-average common shares outstanding (thousands), diluted	58,950	57,414
Earnings per common share attributable to Avista Corporation:
Basic	$ 0.66	$ 0.73
Diluted	$ 0.65	$ 0.73
Dividends paid per common share	$ 0.29	$ 0.275