Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$ 46,462us-gaap_ProfitLoss	$ 48,981us-gaap_ProfitLoss
Other Comprehensive Income (Loss):
Unrealized investment gains/(losses) - net of taxes	0	785
Reclassification adjustment for realized gains on investment securities included in net income - net of taxes	0	(2)
Change in unfunded benefit obligation for pension and other postretirement benefit plans - net of taxes	246	111
Total other comprehensive loss	246	894
Comprehensive income	46,708	49,875
Comprehensive income attributable to noncontrolling interests	(13)	(482)
Comprehensive income attributable to Avista Corporation shareholders	$ 46,695us-gaap_ComprehensiveIncomeNetOfTax	$ 49,393us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

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Amount after tax, before reclassification adjustments, of unrealized holding gain (loss) on available-for-sale securities.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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