Schedule II - Consolidated Valuation and Qualifying Accounts Schedule II - Consolidated Valuation and Qualifying Accounts Level 4 (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reserve for uncollectibe accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance		$ 2,104	$ 2,502	$ 1,873
Valuation Allowances and Reserves, Charged to Income		(3,327)	(6,756)	(5,777)
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		(819)	(198)	(38)
Valuation Allowances and Reserves, Deductions	[1]	4,895	7,352	5,110
Valuation Allowances and Reserves, Ending Balance		1,355	2,104	2,502
Reserve for uncollectible notes
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance		552	885	1,260
Valuation Allowances and Reserves, Charged to Income		0	(333)	(375)
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		0	0	0
Valuation Allowances and Reserves, Deductions	[1]	0	0	0
Valuation Allowances and Reserves, Ending Balance		552	552	885
Reserve for Rate Refunds
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance		0	398	0
Valuation Allowances and Reserves, Charged to Income			(398)	(398)
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts			0	0
Valuation Allowances and Reserves, Deductions	[1]		0	0
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		1,995	1,671	5,480
Valuation Allowances and Reserves, Charged to Income		(890)	(461)	(913)
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		0	0	0
Valuation Allowances and Reserves, Deductions	[1]	1,011	137	4,722
Valuation Allowances and Reserves, Ending Balance		1,874	1,995	1,671
Idaho Power Company | Reserve for uncollectibe accounts
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance		2,104	2,502	1,873
Valuation Allowances and Reserves, Charged to Income		(3,327)	(6,756)	(5,777)
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		(819)	(198)	(38)
Valuation Allowances and Reserves, Deductions	[1]	4,895	7,352	5,110
Valuation Allowances and Reserves, Ending Balance		1,355	2,104	2,502
Idaho Power Company | Reserve for Rate Refunds
Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance		0	398	0
Valuation Allowances and Reserves, Charged to Income			(398)	(398)
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts			0	0
Valuation Allowances and Reserves, Deductions	[1]		0	0
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		1,995	1,671	5,480
Valuation Allowances and Reserves, Charged to Income		(890)	(461)	(913)
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		0	0	0
Valuation Allowances and Reserves, Deductions	[1]	1,011	137	4,722
Valuation Allowances and Reserves, Ending Balance		$ 1,874	$ 1,995	$ 1,671

[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.