v3.26.1
Loans Receivable And Allowance For Credit Losses (Delinquent Loans) (Details) - USD ($)
$ in Thousands
Mar. 31, 2026
Sep. 30, 2025
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One $ 640,990 $ 1,033,723
Year Two 954,820 560,108
Year Three 489,733 1,067,458
Year Four 877,469 1,215,877
Year Five 1,165,848 1,385,026
Prior Years 3,876,625 2,748,460
Revolving Line of Credit 127,716 117,327
Revolving Line of Credit Converted to Term Loan 7,603 8,021
Total Amortized Cost 8,140,804 8,136,000
Financial Asset, Not Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Total Amortized Cost 8,115,385 8,115,913
Financial Asset, 30 to 89 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Total Amortized Cost 11,915 12,363
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Total Amortized Cost 13,504 7,724
One- to Four-Family Segment [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 118,393 233,573
Year Two 227,503 233,389
Year Three 211,670 601,344
Year Four 565,970 972,071
Year Five 933,385 1,266,835
Prior Years 3,659,951 2,607,234
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 5,716,872 5,914,446
One- to Four-Family Segment [Member] | Originated [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Total Amortized Cost 3,679,335 3,776,443
One- to Four-Family Segment [Member] | Originated [Member] | Financial Asset, Not Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 118,393 233,573
Year Two 227,074 232,879
Year Three 211,170 298,045
Year Four 280,728 530,487
Year Five 509,450 740,699
Prior Years 2,321,790 1,730,689
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 3,668,605 3,766,372
One- to Four-Family Segment [Member] | Originated [Member] | Financial Asset, 30 to 89 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 429 0
Year Three 0 66
Year Four 0 908
Year Five 791 473
Prior Years 5,388 5,873
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 6,608 7,320
One- to Four-Family Segment [Member] | Originated [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 0 0
Year Three 0 0
Year Four 65 0
Year Five 18 107
Prior Years 4,039 2,644
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 4,122 2,751
One- to Four-Family Segment [Member] | Correspondent Purchased [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Total Amortized Cost 1,927,514 2,023,397
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Financial Asset, Not Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 0 510
Year Three 500 302,960
Year Four 284,357 440,138
Year Five 421,760 525,556
Prior Years 1,213,593 749,725
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 1,920,210 2,018,889
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Financial Asset, 30 to 89 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 0 0
Year Three 0 273
Year Four 110 161
Year Five 526 0
Prior Years 1,336 2,664
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 1,972 3,098
One- to Four-Family Segment [Member] | Correspondent Purchased [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 0 0
Year Three 0 0
Year Four 710 377
Year Five 840 0
Prior Years 3,782 1,033
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 5,332 1,410
One- to Four-Family Segment [Member] | Bulk Purchased [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Total Amortized Cost 110,023 114,606
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Financial Asset, Not Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 0 0
Year Three 0 0
Year Four 0 0
Year Five 0 0
Prior Years 109,263 114,315
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 109,263 114,315
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Financial Asset, 30 to 89 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 0 0
Year Three 0 0
Year Four 0 0
Year Five 0 0
Prior Years 421 156
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 421 156
One- to Four-Family Segment [Member] | Bulk Purchased [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 0 0
Year Three 0 0
Year Four 0 0
Year Five 0 0
Prior Years 339 135
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 339 135
Commercial Segment [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 518,709 790,804
Year Two 719,945 319,284
Year Three 271,791 461,181
Year Four 307,332 239,182
Year Five 228,562 116,952
Prior Years 213,641 139,000
Revolving Line of Credit 49,776 41,536
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 2,309,756 2,107,939
Commercial Segment [Member] | Commercial Real Estate [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Total Amortized Cost 2,077,923 1,898,183
Commercial Segment [Member] | Commercial Real Estate [Member] | Financial Asset, Not Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 479,122 687,104
Year Two 631,615 292,556
Year Three 247,955 434,882
Year Four 283,252 223,812
Year Five 215,884 111,227
Prior Years 204,326 134,468
Revolving Line of Credit 11,559 9,775
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 2,073,713 1,893,824
Commercial Segment [Member] | Commercial Real Estate [Member] | Financial Asset, 30 to 89 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 471 0
Year Two 0 344
Year Three 87 0
Year Four 0 852
Year Five 0 40
Prior Years 1,012 0
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 1,570 1,236
Commercial Segment [Member] | Commercial Real Estate [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 0 142
Year Three 259 217
Year Four 217 0
Year Five 160 105
Prior Years 1,806 2,609
Revolving Line of Credit 198 50
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 2,640 3,123
Commercial Segment [Member] | Commercial and Industrial [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Total Amortized Cost 231,833 209,756
Commercial Segment [Member] | Commercial and Industrial [Member] | Financial Asset, Not Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 39,116 103,700
Year Two 87,674 26,100
Year Three 23,359 26,082
Year Four 23,850 14,486
Year Five 12,464 5,580
Prior Years 6,497 1,923
Revolving Line of Credit 37,100 31,642
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 230,060 209,513
Commercial Segment [Member] | Commercial and Industrial [Member] | Financial Asset, 30 to 89 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 656 0
Year Three 0 0
Year Four 13 32
Year Five 54 0
Prior Years 0 0
Revolving Line of Credit 50 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 773 32
Commercial Segment [Member] | Commercial and Industrial [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 0 142
Year Three 131 0
Year Four 0 0
Year Five 0 0
Prior Years 0 0
Revolving Line of Credit 869 69
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 1,000 211
Consumer Segment [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 3,888 9,346
Year Two 7,372 7,435
Year Three 6,272 4,933
Year Four 4,167 4,624
Year Five 3,901 1,239
Prior Years 3,033 2,226
Revolving Line of Credit 77,940 75,791
Revolving Line of Credit Converted to Term Loan 7,603 8,021
Total Amortized Cost 114,176 113,615
Consumer Segment [Member] | Home Equity [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Total Amortized Cost 106,849 105,179
Consumer Segment [Member] | Home Equity [Member] | Financial Asset, Not Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 2,347 5,709
Year Two 4,974 5,481
Year Three 4,891 3,546
Year Four 3,209 3,755
Year Five 3,218 1,064
Prior Years 2,925 2,171
Revolving Line of Credit 77,316 75,137
Revolving Line of Credit Converted to Term Loan 7,368 7,826
Total Amortized Cost 106,248 104,689
Consumer Segment [Member] | Home Equity [Member] | Financial Asset, 30 to 89 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 85 51
Year Three 0 0
Year Four 0 0
Year Five 15 0
Prior Years 0 0
Revolving Line of Credit 247 198
Revolving Line of Credit Converted to Term Loan 201 195
Total Amortized Cost 548 444
Consumer Segment [Member] | Home Equity [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 0
Year Two 0 0
Year Three 0 0
Year Four 0 0
Year Five 0 0
Prior Years 0 6
Revolving Line of Credit 19 40
Revolving Line of Credit Converted to Term Loan 34 0
Total Amortized Cost 53 46
Consumer Segment [Member] | Other [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Total Amortized Cost 7,327 8,436
Consumer Segment [Member] | Other [Member] | Financial Asset, Not Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 1,538 3,615
Year Two 2,310 1,847
Year Three 1,369 1,353
Year Four 942 856
Year Five 662 175
Prior Years 107 49
Revolving Line of Credit 358 416
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 7,286 8,311
Consumer Segment [Member] | Other [Member] | Financial Asset, 30 to 89 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 0 15
Year Two 1 42
Year Three 0 20
Year Four 16 0
Year Five 6 0
Prior Years 0 0
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost 23 77
Consumer Segment [Member] | Other [Member] | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]    
Financing Receivable, Credit Quality Indicator [Line Items]    
Year One 3 7
Year Two 2 14
Year Three 12 14
Year Four 0 13
Year Five 0 0
Prior Years 1 0
Revolving Line of Credit 0 0
Revolving Line of Credit Converted to Term Loan 0 0
Total Amortized Cost $ 18 $ 48