Committed Lines of Credit (Tables)

12 Months Ended

Dec. 31, 2019

Avista Utilities [Member]

Line of Credit Facility [Line Items]

Schedule of Line of Credit Facilities [Table Text Block]

Balances outstanding and interest rates of borrowings (excluding letters of credit) under the Company’s revolving committed lines of credit were as follows as of December 31 (dollars in thousands):

	2019			2018
Balance outstanding at end of period	$	182,300		$	190,000
Letters of credit outstanding at end of period	$	21,473		$	10,503
Average interest rate at end of period	2.64		%	3.18		%

Alaska Electric Light & Power [Member]

Line of Credit Facility [Line Items]

Schedule of Line of Credit Facilities [Table Text Block]

Balances outstanding and interest rates of borrowings under AEL&P's revolving committed lines of credit were as follows as of December 31 (dollars in thousands):

	2019			2018
Balance outstanding at end of period	$	3,500		$	—
Average interest rate at end of period	3.45		%	—		%