LOANS & ALLOWANCE FOR CREDIT LOSSES-LOANS - LOANS BY AMORTIZED COST BASIS BY YEAR OF ORIGINATION AND CREDIT QUALITY INDICATOR (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Jun. 30, 2020
Financing Receivable, Credit Quality Indicator [Line Items]
2021	$ 3,162,591
2020	2,569,517
2019	1,466,370
2018	984,121
2017	595,843
Prior	1,048,517
Revolving Loans	1,727,785
Revolving Loans Converted to Loans HFI	0
Total	$ 11,554,744	$ 10,703,442
As a % of total gross loans and leases
2021	27.37%
2020	22.24%
2019	12.69%
2018	8.52%
2017	5.16%
Prior	9.07%
Revolving Loans	14.95%
Revolving Loans Converted to Loans HFI	0.00%
Total	100.00%
Single Family - Mortgage & Warehouse
Financing Receivable, Credit Quality Indicator [Line Items]
2021	$ 962,866
2020	769,276
2019	515,909
2018	492,004
2017	372,740
Prior	632,553
Revolving Loans	614,124
Revolving Loans Converted to Loans HFI	0
Total	4,359,472	4,722,304
Multifamily and Commercial Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	641,817
2020	609,877
2019	377,100
2018	300,107
2017	197,814
Prior	343,739
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	2,470,454	2,263,054
Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
2021	1,335,963
2020	980,924
2019	482,786
2018	130,818
2017	0
Prior	63,750
Revolving Loans	186,212
Revolving Loans Converted to Loans HFI	0
Total	3,180,453	2,297,920
Commercial & Industrial - Non-RE
Financing Receivable, Credit Quality Indicator [Line Items]
2021	48,385
2020	92,565
2019	20,046
2018	26,745
2017	8,679
Prior	0
Revolving Loans	927,449
Revolving Loans Converted to Loans HFI	0
Total	1,123,869	885,320
Auto & Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2021	156,482
2020	78,966
2019	70,529
2018	32,784
2017	15,961
Prior	7,458
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	362,180	341,365
Other
Financing Receivable, Credit Quality Indicator [Line Items]
2021	17,078
2020	37,909
2019	0
2018	1,663
2017	649
Prior	1,017
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	58,316	$ 193,479
Pass
Financing Receivable, Credit Quality Indicator [Line Items]
2021	3,154,485
2020	2,441,883
2019	1,367,747
2018	932,562
2017	571,744
Prior	988,927
Revolving Loans	1,697,453
Revolving Loans Converted to Loans HFI	0
Total	11,154,801
Pass | Single Family - Mortgage & Warehouse
Financing Receivable, Credit Quality Indicator [Line Items]
2021	962,787
2020	726,941
2019	492,421
2018	470,287
2017	351,274
Prior	576,197
Revolving Loans	585,785
Revolving Loans Converted to Loans HFI	0
Total	4,165,692
Pass | Multifamily and Commercial Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	636,870
2020	571,530
2019	357,900
2018	288,698
2017	195,257
Prior	340,553
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	2,390,808
Pass | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
2021	1,335,963
2020	946,723
2019	430,513
2018	114,979
2017	0
Prior	63,750
Revolving Loans	184,219
Revolving Loans Converted to Loans HFI	0
Total	3,076,147
Pass | Commercial & Industrial - Non-RE
Financing Receivable, Credit Quality Indicator [Line Items]
2021	45,396
2020	80,139
2019	16,842
2018	24,210
2017	8,679
Prior	0
Revolving Loans	927,449
Revolving Loans Converted to Loans HFI	0
Total	1,102,715
Pass | Auto & Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2021	156,391
2020	78,641
2019	70,071
2018	32,725
2017	15,885
Prior	7,410
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	361,123
Pass | Other
Financing Receivable, Credit Quality Indicator [Line Items]
2021	17,078
2020	37,909
2019	0
2018	1,663
2017	649
Prior	1,017
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	58,316
Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
2021	109
2020	57,392
2019	41,045
2018	7,145
2017	7,755
Prior	19,787
Revolving Loans	30,332
Revolving Loans Converted to Loans HFI	0
Total	163,565
Special Mention | Single Family - Mortgage & Warehouse
Financing Receivable, Credit Quality Indicator [Line Items]
2021	79
2020	9,972
2019	7,102
2018	4,093
2017	6,434
Prior	18,347
Revolving Loans	28,339
Revolving Loans Converted to Loans HFI	0
Total	74,366
Special Mention | Multifamily and Commercial Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	26,224
2019	18,132
2018	855
2017	1,321
Prior	1,409
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	47,941
Special Mention | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	9,359
2019	15,487
2018	0
2017	0
Prior	0
Revolving Loans	1,993
Revolving Loans Converted to Loans HFI	0
Total	26,839
Special Mention | Commercial & Industrial - Non-RE
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	11,693
2019	262
2018	2,197
2017	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	14,152
Special Mention | Auto & Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2021	30
2020	144
2019	62
2018	0
2017	0
Prior	31
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	267
Special Mention | Other
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	0
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
2021	7,997
2020	70,242
2019	57,578
2018	44,414
2017	16,344
Prior	39,803
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	236,378
Substandard | Single Family - Mortgage & Warehouse
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	32,363
2019	16,386
2018	17,624
2017	15,032
Prior	38,009
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	119,414
Substandard | Multifamily and Commercial Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	4,947
2020	12,123
2019	1,068
2018	10,554
2017	1,236
Prior	1,777
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	31,705
Substandard | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	24,842
2019	36,786
2018	15,839
2017	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	77,467
Substandard | Commercial & Industrial - Non-RE
Financing Receivable, Credit Quality Indicator [Line Items]
2021	2,989
2020	733
2019	2,942
2018	338
2017	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	7,002
Substandard | Auto & Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2021	61
2020	181
2019	396
2018	59
2017	76
Prior	17
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	790
Substandard | Other
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	0
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	0
Doubtful | Single Family - Mortgage & Warehouse
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	0
Doubtful | Multifamily and Commercial Mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	0
Doubtful | Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	0
Doubtful | Commercial & Industrial - Non-RE
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	0
Doubtful | Auto & Consumer
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	0
Doubtful | Other
Financing Receivable, Credit Quality Indicator [Line Items]
2021	0
2020	0
2019	0
2018	0
2017	0
Prior	0
Revolving Loans	0
Revolving Loans Converted to Loans HFI	0
Total	$ 0