Selected Quarterly Financial Data (Tables)

12 Months Ended

Dec. 31, 2014

Selected Quarterly Financial Information [Abstract]

Summary of Quarterly Operations

	Three Months Ended
	March 31			June 30		September 30			December 31
2014
Operating revenues from continuing operations	$	446,578		$	312,580	$	301,558		$	411,846
Operating expenses from continuing operations	356,236			249,849		268,796			345,093
Income from continuing operations	$	90,342		$	62,731	$	32,762		$	66,753
Net income from continuing operations	$	47,466		$	31,270	$	10,526		$	30,604
Net income (loss) from discontinued operations	1,515			69,312		(55		)	1,639
Net income	48,981			100,582		10,471			32,243
Net loss (income) attributable to noncontrolling interests	(482		)	289		(20		)	(23		)
Net income attributable to Avista Corporation shareholders	$	48,499		$	100,871	$	10,451		$	32,220
Amounts attributable to Avista Corp. shareholders:
Net income from continuing operations attributable to Avista Corp. shareholders	$	47,476		$	31,254	$	10,506		$	30,581
Net income (loss) from discontinued operations attributable to Avista Corp. shareholders	1,023			69,617		(55		)	1,639
Net income attributable to Avista Corp. shareholders	$	48,499		$	100,871	$	10,451		$	32,220
Outstanding common stock:
Weighted average, basic	60,122			60,184		63,934			62,290
Weighted average, diluted	60,168			60,463		64,244			62,671
Earnings per common share attributable to Avista Corp. shareholders, diluted:
Earnings per common share from continuing operations	$	0.79		$	0.52	$	0.16		$	0.48
Earnings per common share from discontinued operations	0.02			1.15		—			0.03
Total earnings per common share attributable to Avista Corp. shareholders, diluted	$	0.81		$	1.67	$	0.16		$	0.51

	Three Months Ended
	March 31			June 30			September 30			December 31
2013
Operating revenues from continuing operations	$	440,499		$	307,488		$	289,477		$	404,280
Operating expenses from continuing operations	358,361			252,518			259,650			340,126
Income from continuing operations	$	82,138		$	54,970		$	29,827		$	64,154
Net income from continuing operations	$	41,219		$	24,239		$	8,483		$	30,392
Net income from discontinued operations	1,882			1,491			3,448			1,140
Net income	43,101			25,730			11,931			31,532
Net loss (income) attributable to noncontrolling interests	(760		)	(73		)	(518		)	134
Net income attributable to Avista Corporation shareholders	$	42,341		$	25,657		$	11,413		$	31,666
Amounts attributable to Avista Corp. shareholders:
Net income from continuing operations attributable to Avista Corp. shareholders	$	41,220		$	24,212		$	8,450		$	30,391
Net income from discontinued operations attributable to Avista Corp. shareholders	1,121			1,445			2,963			1,275
Net income attributable to Avista Corp. shareholders	$	42,341		$	25,657		$	11,413		$	31,666
Outstanding common stock:
Weighted average, basic	59,866			59,937			59,994			60,037
Weighted average, diluted	59,898			59,962			60,032			60,087
Earnings per common share attributable to Avista Corp. shareholders, diluted:
Earnings per common share from continuing operations	$	0.69		$	0.40		$	0.14		$	0.51
Earnings per common share from discontinued operations	0.02			0.03			0.05			0.02
Total earnings per common share attributable to Avista Corp. shareholders, diluted	$	0.71		$	0.43		$	0.19		$	0.53