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, 2020	Dec. 31, 2019	Dec. 31, 2018
Reserve for uncollectibe accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance		$ 1,744	$ 1,989	$ 2,193
Valuation Allowances and Reserves, Charged to Income		5,239	2,381	3,363
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		438	227	392
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	[1]	2,158	2,853	3,959
Valuation Allowances and Reserves, Ending Balance		5,263	1,744	1,989
Injuries and damages
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance		1,748	1,877	1,469
Valuation Allowances and Reserves, Charged to Income		1,203	390	855
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		0	0	0
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	[1]	467	519	447
Valuation Allowances and Reserves, Ending Balance		2,484	1,748	1,877
Idaho Power Company | Reserve for uncollectibe accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance		1,744	1,989	2,193
Valuation Allowances and Reserves, Charged to Income		5,239	2,381	3,363
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		438	227	392
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	[1]	2,158	2,853	3,959
Valuation Allowances and Reserves, Ending Balance		5,263	1,744	1,989
Idaho Power Company | Injuries and damages
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance		1,748	1,877	1,469
Valuation Allowances and Reserves, Charged to Income		1,203	390	855
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		0	0	0
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	[1]	467	519	447
Valuation Allowances and Reserves, Ending Balance		$ 2,484	$ 1,748	$ 1,877

[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 reserved.