Schedule II - Consolidated Valuation and Qualifying Accounts Schedule II - Consolidated Valuation and Qualifying Accounts Level 4 (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Reserve for uncollectibe accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance	$ 2,502		$ 1,873		$ 1,435
Valuation Allowances and Reserves, Charged to Income	6,756		5,777		4,524
Valuation Allowances and Reserves, Charged to Other Accounts	198		(38)		283
Valuation Allowances and Reserves, Deductions	7,352	[1]	5,110	[1]	4,369	[1]
Valuation Allowances and Reserves, Ending Balance	2,104		2,502		1,873
Reserve for uncollectible notes
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance	885		1,260		2,743
Valuation Allowances and Reserves, Charged to Income	(333)		(375)		(1,483)
Valuation Allowances and Reserves, Charged to Other Accounts	0		0		0
Valuation Allowances and Reserves, Deductions	0	[1]	0	[1]	0	[1]
Valuation Allowances and Reserves, Ending Balance	552		885		1,260
Reserve for Rate Refunds
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance	398		0
Valuation Allowances and Reserves, Charged to Income	(398)		398
Valuation Allowances and Reserves, Charged to Other Accounts	0		0
Valuation Allowances and Reserves, Deductions	0	[1]	0	[1]
Valuation Allowances and Reserves, Ending Balance	0		398
Injuries and damages
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance	1,671		5,480		1,925
Valuation Allowances and Reserves, Charged to Income	461		913		4,481
Valuation Allowances and Reserves, Charged to Other Accounts	0		0		0
Valuation Allowances and Reserves, Deductions	137	[1]	4,722	[1]	926	[1]
Valuation Allowances and Reserves, Ending Balance	1,995		1,671		5,480
Idaho Power Company | Reserve for uncollectibe accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance	2,502		1,873		1,435
Valuation Allowances and Reserves, Charged to Income	6,756		5,777		4,524
Valuation Allowances and Reserves, Charged to Other Accounts	198		(38)		283
Valuation Allowances and Reserves, Deductions	7,352	[1]	5,110	[1]	4,369	[1]
Valuation Allowances and Reserves, Ending Balance	2,104		2,502		1,873
Idaho Power Company | Reserve for Rate Refunds
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance	398		0
Valuation Allowances and Reserves, Charged to Income	(398)		398
Valuation Allowances and Reserves, Charged to Other Accounts	0		0
Valuation Allowances and Reserves, Deductions	0	[1]	0	[1]
Valuation Allowances and Reserves, Ending Balance	0		398
Idaho Power Company | Injuries and damages
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance	1,671		5,480		1,925
Valuation Allowances and Reserves, Charged to Income	461		913		4,481
Valuation Allowances and Reserves, Charged to Other Accounts	0		0		0
Valuation Allowances and Reserves, Deductions	137	[1]	4,722	[1]	926	[1]
Valuation Allowances and Reserves, Ending Balance	$ 1,995		$ 1,671		$ 5,480

[1] Represents deductions from the reserves for purposes for which the reserves were created. In the case of uncollectible accounts, and notes reserves, includes reversals of amounts previously written off.