XML 126 R88.htm IDEA: XBRL DOCUMENT
v3.21.2

401(k) Plan (Details) - USD ($) | 12 Months Ended
--- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2019
Retirement Benefits [Abstract] |  |  |
Employee contribution, percentage of annual salary | 100.00% |  |
Employee contribution, maximum allowable contribution | $ 58,000 |  |
Service period for participation eligibility | 30 days |  |
Service period for eligibility of profit sharing or matching contributions | 1 year |  |
Employer matching contribution percent | 100.00% |  |
Percent of employees' gross pay | 4.00% |  |
Profit sharing contribution, vesting schedule (in years) | 6 years |  |
Profit sharing contribution, percent | 7.00% |  |
Company contributions to plan | $ 9,905,000 | $ 8,333,000 | $ 6,920,000

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

X
- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
Name: | us-gaap_DefinedContributionPlanCostRecognized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage employer matches of the employee's percentage contribution matched. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Maximum amount the employee may contribute to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeeAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Maximum percentage of employee gross pay the employee may contribute to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanMaximumAnnualContributionsPerEmployeePercent
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Contribution Plan, Maximum Annual Employer Profit Sharing Contribution, Percent + References No definition available. + Details
Name: | wfsl_DefinedContributionPlanMaximumAnnualEmployerProfitSharingContributionPercent
Namespace Prefix: | wfsl_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Contribution Plan, Service Period for Eligibility of Profit Sharing or Matching Contributions + References No definition available. + Details
Name: | wfsl_DefinedContributionPlanServicePeriodForEligibilityOfProfitSharingOrMatchingContributions
Namespace Prefix: | wfsl_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Defined Contribution Plan, Service Period for Participation Eligibility + References No definition available. + Details
Name: | wfsl_DefinedContributionPlanServicePeriodForParticipationEligibility
Namespace Prefix: | wfsl_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Term for Employees to Become Fully Vested + References No definition available. + Details
Name: | wfsl_TermForEmployeesToBecomeFullyVested
Namespace Prefix: | wfsl_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration