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, 2019	Dec. 31, 2018	Dec. 31, 2017
Reserve for uncollectibe accounts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance		$ 1,989	$ 2,193	$ 1,132
Valuation Allowances and Reserves, Charged to Income		2,381	3,363	5,753
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		227	392	324
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	[1]	2,853	3,959	5,016
Valuation Allowances and Reserves, Ending Balance		1,744	1,989	2,193
Injuries and damages
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance		1,877	1,469	1,792
Valuation Allowances and Reserves, Charged to Income		390	855	687
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		0	0	0
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	[1]	519	447	1,010
Valuation Allowances and Reserves, Ending Balance		1,748	1,877	1,469
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		1,989	2,193	1,132
Valuation Allowances and Reserves, Charged to Income		2,381	3,363	5,753
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		227	392	324
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	[1]	2,853	3,959	5,016
Valuation Allowances and Reserves, Ending Balance		1,744	1,989	2,193
Idaho Power Company | Injuries and damages
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Valuation Allowances and Reserves, Beginning Balance		1,877	1,469	1,792
Valuation Allowances and Reserves, Charged to Income		390	855	687
Valuation Allowances and Reserves, Charged (Credited) to Other Accounts		0	0	0
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	[1]	519	447	1,010
Valuation Allowances and Reserves, Ending Balance		$ 1,748	$ 1,877	$ 1,469

[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.