Business Combination - Schedule of Purchase Price Consideration (Details) - Luther Burbank $ / shares in Units, shares in Thousands, $ in Thousands	Mar. 01, 2024 USD ($) $ / shares shares
Business Acquisition [Line Items]
Number of WaFd shares issued to LBC shareholders \| shares	17,089
WaFd market price per share on February 29, 2024 (in dollars per share) \| $ / shares	$ 27.24
Purchase price of shares issued to LBC shareholders	$ 465,501
Cash in lieu of fractional shares	3
Purchase price consideration	$ 465,504

Number of shares of equity interests issued or issuable to acquire entity.

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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.

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Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

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Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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