SEGMENT INFORMATION: Level 4 (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Segment Reporting Information
Revenues	$ 308,045	$ 308,468	$ 793,031	$ 801,719
Revenues	309,630	309,357	796,107	804,073
Income (loss) attributable to IDACORP, Inc.	107,414	67,125	157,878	122,219
Income (loss) attributable to IDACORP, Inc.	107,067	67,135	157,708	122,407
Total assets	4,826,935		4,826,935		4,676,055
Idaho Power Company [Member] | Idaho Power Company
Segment Reporting Information
Revenues	308,045	308,468	793,031	801,719
Income (loss) attributable to IDACORP, Inc.	104,872	64,650	155,420	121,700
Total assets	4,719,173		4,719,173
All Other
Segment Reporting Information
Revenues	1,585	889	3,076	2,354
Income (loss) attributable to IDACORP, Inc.	2,195	2,485	2,288	707
Total assets	124,273		124,273
Eliminations
Segment Reporting Information
Revenues	0	0	0	0
Income (loss) attributable to IDACORP, Inc.	0	0	0	0
Total assets	(16,511)		(16,511)
Idaho Power Company [Member]
Segment Reporting Information
Revenues	308,045	308,468	793,031	801,719
Income (loss) attributable to IDACORP, Inc.	104,872	64,650	155,420	121,700
Total assets	$ 4,719,173		$ 4,719,173		$ 4,568,393
Bridger Coal Company
Segment Reporting Information
IERCo's ownership percentage in Bridger Coal Company	33.00%