LOANS & ALLOWANCE FOR CREDIT LOSSES - UNPAID PRINCIPAL BALANCE FOR PERFORMING AND NONACCRUAL (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Jun. 30, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 16,652,026	$ 14,253,676
Nonaccrual loans to total loans (as a percent)	0.52%	0.83%
Single Family - Mortgage & Warehouse
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 4,173,833	$ 3,988,462
Multifamily and Commercial Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3,082,225	2,877,680
Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	6,199,818	4,781,044
Commercial & Industrial - Non-RE
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,639,650	2,028,128
Auto & Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	546,264	567,228
Other
Financing Receivable, Credit Quality Indicator [Line Items]
Total	10,236	11,134
Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Total	16,564,866	14,135,482
Performing | Single Family - Mortgage & Warehouse
Financing Receivable, Credit Quality Indicator [Line Items]
Total	4,143,119	3,922,038
Performing | Multifamily and Commercial Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total	3,047,122	2,844,270
Performing | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	6,184,966	4,766,192
Performing | Commercial & Industrial - Non-RE
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,636,661	2,025,139
Performing | Auto & Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	544,807	566,789
Performing | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Total	8,191	11,054
Nonaccrual
Financing Receivable, Credit Quality Indicator [Line Items]
Total	87,160	118,194
Nonaccrual | Single Family - Mortgage & Warehouse
Financing Receivable, Credit Quality Indicator [Line Items]
Total	30,714	66,424
Nonaccrual | Multifamily and Commercial Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total	35,103	33,410
Nonaccrual | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	14,852	14,852
Nonaccrual | Commercial & Industrial - Non-RE
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,989	2,989
Nonaccrual | Auto & Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,457	439
Nonaccrual | Other
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 2,045	$ 80