Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 10,471	$ 11,931	$ 160,034	$ 80,762
Other Comprehensive Income (Loss):
Unrealized investment gains/(losses) - net of taxes	0	(395)	1,126	(1,687)
Reclassification adjustment for realized gains on investment securities included in net income - net of taxes	0	(1)	(2)	(12)
Reclassification adjustment for realized losses on investment securities net of taxes			462	0
Change in unfunded benefit obligation for pension and other postretirement benefit plans - net of taxes	112	184	335	551
Total other comprehensive loss	112	(212)	1,921	(1,148)
Comprehensive income	10,583	11,719	161,955	79,614
Comprehensive income attributable to noncontrolling interests	(20)	(518)	(213)	(1,351)
Comprehensive income attributable to Avista Corporation shareholders	$ 10,563	$ 11,201	$ 161,742	$ 78,263