XML 52 R42.htm IDEA: XBRL DOCUMENT
v3.19.2

Derivatives and Hedging Activities - Impact of Fair Value Hedge Accounting on the Carrying Value of the Hedged Items (Details) - Commercial loan fair value hedges $ in Thousands | Jun. 30, 2019 USD ($)
--- | ---
Derivatives, Fair Value [Line Items] |
Carrying value of hedged items | $ 93,271
Cumulative gain (loss) fair value hedge adjustment included in carrying amount of hedged items | (2,585)
Loans receivable |
Derivatives, Fair Value [Line Items] |
Carrying value of hedged items | 93,271
Cumulative gain (loss) fair value hedge adjustment included in carrying amount of hedged items | $ (2,585)

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DerivativesFairValueLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of cumulative increase (decrease) in fair value of hedged asset in fair value hedge, attributable to hedged risk. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4EE -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109999712-113959 + Details
Name: | us-gaap_HedgedAssetFairValueHedgeCumulativeIncreaseDecrease
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of liability hedged in fair value hedging relationship. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4EE -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109980867&loc=SL109999712-113959 + Details
Name: | us-gaap_HedgedLiabilityFairValueHedge
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Details
Name: | us-gaap_DerivativeInstrumentRiskAxis=wfsl_CommercialLoanHedgeMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BalanceSheetLocationAxis=us-gaap_LoansReceivableMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |