LOANS & ALLOWANCE FOR CREDIT LOSSES - SCHEDULE OF COMPOSITION OF LOAN PORTFOLIO (Details) - USD ($) $ in Thousands	Jun. 30, 2024	Dec. 07, 2023	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2021
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	$ 19,802,811		$ 16,652,026
Allowance for credit losses - loans	(260,542)		(166,680)	$ (148,617)	$ (132,958)
Unaccreted premiums (discounts) and loan fees	(310,884)		(28,618)
Total net loans	19,231,385		16,456,728
Single Family - Mortgage & Warehouse
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	4,178,832		4,173,833
Allowance for credit losses - loans	(16,943)		(17,503)	(19,670)	(26,604)
Multifamily and Commercial Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	3,861,931		3,082,225
Allowance for credit losses - loans	(70,771)		(16,848)	(14,655)	(13,146)
Multifamily and Commercial Mortgage | Real Estate Loan Portfolios
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	284,000
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	6,088,622		6,199,818
Allowance for credit losses - loans	(87,780)		(72,755)	(69,339)	(57,928)
Commercial Real Estate | Real Estate Loan Portfolios
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	44,500
Total net loans		$ 1,300,000
Commercial & Industrial - Non-RE
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	5,241,766		2,639,650
Allowance for credit losses - loans	(76,032)		(46,347)	(30,808)	(28,460)
Auto & Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total	431,660		556,500
Allowance for credit losses - loans	$ (9,016)		$ (13,227)	$ (14,145)	$ (6,820)