Summary of Significant Accounting Policies (Policies)	3 Months Ended
Summary of Significant Accounting Policies (Policies)	Dec. 31, 2014
Accounting Policies [Abstract]
Basis of Accounting	Basis of Presentation - The unaudited interim financial statements included in this report have been prepared by Washington Federal. All intercompany transactions and accounts have been eliminated in consolidation. The preparation of financial statements in conformity with accounting principles generally accepted in the United States of America (“GAAP”) requires management to make estimates and assumptions that affect amounts reported in the financial statements. Actual results could differ from these estimates. In the opinion of management, all adjustments (consisting only of normal recurring accruals) necessary for a fair presentation are reflected in the interim financial statements. The September 30, 2014 Consolidated Statement of Financial Condition was derived from audited financial statements. The information included in this Form 10-Q should be read in conjunction with the financial statements and related notes in the Company’s 2014 Annual Report on Form 10-K (“2014 Form 10-K”) as filed with the SEC. Interim results are not necessarily indicative of results for a full year.
Off-Balance-Sheet Credit Exposures	The Company estimates losses on off-balance-sheet credit exposures by allocating a loss percentage derived from historical loss factors for each asset class.
New Accounting Pronouncements	In June 2014, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") 2014-11, Transfers and Servicing (Topic 860) - Repurchase to Maturity Transactions, Repurchase Financings, and Disclosures. Under this new accounting guidance, repurchase-to-maturity transactions will be accounted for as secured borrowings rather than sales of an asset, and transfers of financial assets with contemporaneous repurchase financings will no longer be evaluated to determine whether they should be accounted for on a combined basis as forward contracts. The new guidance also prescribes additional disclosures particularly on the nature of collateral pledged in repurchase financings accounted for as secured borrowings. The amendments in this update will be effective for the first interim or annual period beginning after December 31, 2014, with the exception of the collateral disclosures which will be effective for interim periods beginning after March 15, 2015. Early application is not permitted. The Company does not expect this guidance to have a material impact on its consolidated financial statements. In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers (Topic 606). This new accounting guidance clarifies the principles for recognizing revenue from contracts with customers. The new accounting guidance does not apply to financial instruments. For public companies, this update will be effective for interim and annual periods beginning after December 15, 2016. The Company does not expect the new guidance to have a material impact on its consolidated financial statements. In January 2014, the FASB issued ASU 2014-04, Receivables - Troubled Debt Restructurings by Creditors (Subtopic 310-40) - Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure. This new guidance clarifies that if an in substance repossession or foreclosure occurs, a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan, upon either: (a) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure; or (b) the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. ASU 2014-04 is effective for annual and interim reporting periods within those annual periods, beginning after December 15, 2014. Adoption of the new guidance is not expected to have a significant impact on the Company’s consolidated financial statements.