Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net income	$ 11,931	$ 5,962	$ 80,762	$ 62,707
Other Comprehensive Income (Loss):
Unrealized investment gains - net of taxes	(395)	110	(1,687)	409
Reclassification adjustment for realized gains on investment securities included in net income - net of taxes	(1)	(17)	(12)	(158)
Change in unfunded benefit obligation for pension and other postretirement benefit plans - net of taxes	184	168	551	489
Total other comprehensive loss	(212)	261	(1,148)	740
Comprehensive income	11,719	6,223	79,614	63,447
Comprehensive income attributable to noncontrolling interests	(518)	(176)	(1,351)	(355)
Comprehensive income attributable to Avista Corporation shareholders	$ 11,201	$ 6,047	$ 78,263	$ 63,092