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Summary of Significant Accounting Policies - Narrative (Details)		3 Months Ended
	Mar. 01, 2024 USD ($)	Dec. 31, 2024 USD ($) branch classOfPortfolioSegment portfolioSegment	Sep. 30, 2024 USD ($)
Summary of Significant Accounting Policies [Line Items]
Number of offices | branch		210
Cash collateral		$ 235,860,000	$ 168,200,000
Fair value of NAV		35,271,845
Remaining unfunded commitment		$ 15,119,261
Number of portfolio segments for loans held for investment | portfolioSegment		2
Number of classes disaggregating the commercial loan portfolio | classOfPortfolioSegment		5
Number of classes disaggregating the consumer loan portfolio | classOfPortfolioSegment		5
Goodwill		$ 414,723,000	$ 411,360,000
Luther Burbank
Summary of Significant Accounting Policies [Line Items]
Goodwill	$ 107,890,000
Intangible assets	$ 37,022,000
Acquired intangible assets, useful life	6 years

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