Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 48,981	$ 43,101
Other Comprehensive Income (Loss):
Unrealized investment gains/(losses) - net of taxes	785	(70)
Reclassification adjustment for realized gains on investment securities included in net income - net of taxes	(2)	(1)
Change in unfunded benefit obligation for pension and other postretirement benefit plans - net of taxes	111	184
Total other comprehensive loss	894	113
Comprehensive income	49,875	43,214
Comprehensive income attributable to noncontrolling interests	(482)	(760)
Comprehensive income attributable to Avista Corporation shareholders	$ 49,393	$ 42,454