XML 69 R51.htm IDEA: XBRL DOCUMENT
v3.19.1

Revenue Revenue Utility Related Taxes (Details) - USD ($) $ in Thousands | 3 Months Ended
--- | ---
Mar. 31, 2019 | Mar. 31, 2018
Revenue from Contract with Customer [Abstract] |  |
Public Utility Operating Expenses Excise Taxes Collected | $ 19,089 | $ 19,167

X
- Definition Public Utility Operating Expenses Excise Taxes Collected and Reported Gross in Revenues and Operating Expenses + References No definition available. + Details
Name: | ava_PublicUtilityOperatingExpensesExciseTaxesCollected
Namespace Prefix: | ava_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_RevenueFromContractWithCustomerAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration