v3.26.1
Fair Value Measurements (Tables)
 6 Months Ended
Mar. 31, 2026
Fair Value Disclosures [Abstract]  
Schedule of Fair Value of Assets Measured on Recurring Basis
The following tables present the balance and level in the fair value hierarchy of assets and liabilities that are measured at fair value on a recurring basis (with the exception of those measured using the NAV practical expedient).
 March 31, 2026
 Level 1Level 2Level 3Total
 (In thousands)
Financial Assets
Available-for-sale securities:
U.S. government and agency securities$— $202,727 $— $202,727 
Asset-backed securities— 474,365 — 474,365 
Municipal bonds— 34,743 — 34,743 
Corporate debt securities— 161,884 — 161,884 
Mortgage-backed securities
Agency pass-through certificates— 3,478,539 — 3,478,539 
Total available-for-sale securities— 4,352,258 — 4,352,258 
Client swap program hedges— 34,461 — 34,461 
Mortgage loan fair value hedges— 10,638 — 10,638 
Mortgage backed securities fair value hedges— 294 — 294 
Borrowings cash flow hedges— 97,378 — 97,378 
Total financial assets$— $4,495,029 $— $4,495,029 
Financial Liabilities
Client swap program hedges$— $34,527 $— $34,527 
Mortgage loan fair value hedges— 11,165 — 11,165 
Mortgage backed securities fair value hedges— 8,468 — 8,468 
Total financial liabilities$— $54,160 $— $54,160 
 September 30, 2025
 Level 1Level 2Level 3Total
 (In thousands)
Financial Assets
Available-for-sale securities:
U.S. government and agency securities$— $235,919 $— $235,919 
Asset-backed securities— 506,334 506,334 
Municipal bonds— 35,258 — 35,258 
Corporate debt securities— 152,537 — 152,537 
Mortgage-backed securities
Agency pass-through certificates— 2,603,153 — 2,603,153 
Total available-for-sale securities— 3,533,201 — 3,533,201 
Client swap program hedges— 37,347 — 37,347 
Commercial loan fair value hedges— 1,611 — 1,611 
Mortgage loan fair value hedges— 13,082 — 13,082 
Borrowings cash flow hedges— 99,231 — 99,231 
Total financial assets$— $3,684,472 $— $3,684,472 
Financial Liabilities
Client swap program hedges$— $37,818 $— $37,818 
Mortgage backed securities fair value hedges— 15,086 — 15,086 
Mortgage loan fair value hedges— 20,426 — 20,426 
Total financial liabilities$— $73,330 $— $73,330 
Schedule of Fair Value of Assets Measured on Nonrecurring Basis
The following tables present the aggregated balance of assets that were measured at fair value on a nonrecurring basis at March 31, 2026 and March 31, 2025, and the total gains (losses) resulting from those fair value adjustments during the respective periods. The estimated fair value measurements are shown gross of estimated selling costs.
 
 March 31, 2026Three Months Ended March 31, 2026Six Months Ended March 31, 2026
 Level 1Level  2Level  3TotalTotal Gains (Losses)
 (In thousands)(In thousands)
Collateral Dependent Loans$— $— $11,676 $11,676 $(771)$(5,281)
Real estate owned— — 390 390 — 69 
Balance at end of period$— $— $12,066 $12,066 $(771)$(5,212)


March 31, 2025Three Months Ended March 31, 2025Six Months Ended March 31, 2025
Level 1Level  2Level  3TotalTotal Gains (Losses)
(In thousands)(In thousands)
Collateral Dependent Loans$— $— $9,338 $9,338 $(5,092)$(5,363)
Real estate owned— — — — — — 
Balance at end of period$— $— $9,338 $9,338 $(5,092)$(5,363)
Schedule of Fair Value of Financial Instruments by Balance Sheet Grouping Although management is not aware of any factors that would materially affect the estimated fair value amounts presented below, such amounts have not been comprehensively revalued for purposes of these financial statements since the dates shown, and therefore, estimates of fair value subsequent to those dates may differ significantly from the amounts presented below.
 March 31, 2026September 30, 2025
 Level in Fair Value HierarchyCarrying
Amount		Estimated
Fair Value		Carrying
Amount		Estimated
Fair Value
 ($ in thousands)
Financial assets
Cash and cash equivalents1$669,799 $669,799 $657,310 $657,310 
Available-for-sale securities
U.S. government and agency securities2202,727 202,727 235,919 235,919 
Asset-backed securities2474,365 474,365 506,334 506,334 
Municipal bonds234,743 34,743 35,258 35,258 
Corporate debt securities2161,884 161,884 152,537 152,537 
Mortgage-backed securities
Agency pass-through certificates23,478,539 3,478,539 2,603,153 2,603,153 
Total available-for-sale securities4,352,258 4,352,258 3,533,201 3,533,201 
Held-to-maturity securities
Mortgage-backed securities
Agency pass-through certificates2745,727 712,117 645,802 612,739 
Total held-to-maturity securities745,727 712,117 645,802 612,739 
Loans receivable319,966,983 19,636,861 20,088,618 19,681,909 
FHLB stock2146,351 146,351 88,068 88,068 
        Other assets - client swap program hedges234,461 34,461 37,347 37,347 
        Other assets - commercial fair value loan hedges2— — 1,611 1,611 
        Other assets - mortgage loan fair value hedges210,638 10,638 13,082 13,082 
        Other assets - mortgage backed securities fair value
                               hedges		2294 294 — — 
        Other assets - borrowings cash flow hedges297,378 97,378 99,231 99,231 
Financial liabilities
Time deposits28,377,230 8,363,844 9,131,104 9,121,470 
Borrowings23,062,441 3,060,064 1,765,604 1,755,130 
Junior subordinated debentures352,107 52,093 51,645 50,925 
        Other liabilities - client swap program hedges234,527 34,527 37,818 37,818 
Other liabilities - mortgage loan fair value hedges211,165 11,165 20,426 20,426 
Other liabilities - mortgage backed securities fair value hedges28,468 8,468 15,086 15,086 
Reconciliation of Amortized Cost to Fair Value of Securities
The following tables provide details about the amortized cost and fair value of available-for-sale and held-to-maturity securities.


 March 31, 2026
 Amortized
Cost		Gross UnrealizedFair
Value		Yield
 GainsLosses
 ($ in thousands)
Available-for-sale securities
U.S. government and agency securities due
Within 1 year$1,129 $— $(11)$1,118 2.05 %
1 to 5 years347 — — 347 4.25 
5 to 10 years135,640 301 (4)135,937 4.20 
Over 10 years65,241 224 (140)65,325 4.80 
Asset-backed securities
Within 1 year9,920 — (157)9,763 4.43 
5 to 10 years1,287 — (1)1,286 4.58 
Over 10 years464,284 1,081 (2,049)463,316 4.67 
Corporate debt securities due
1 to 5 years42,508 287 (2,142)40,653 5.43 
5 to 10 years127,732 449 (6,950)121,231 4.14 
Municipal bonds due
1 to 5 years5,643 — (208)5,435 3.00 
5 to 10 years20,000 — (100)19,900 6.45 
Over 10 years9,735 — (327)9,408 4.57 
Mortgage-backed securities
Agency pass-through certificates3,485,607 36,993 (44,061)3,478,539 3.86 
4,369,073 39,335 (56,150)4,352,258 4.00 
Held-to-maturity securities
Mortgage-backed securities
Agency pass-through certificates745,727 3,013 (36,623)712,117 4.04 
$5,114,800 $42,348 $(92,773)$5,064,375 4.01 %
 September 30, 2025
 Amortized
Cost		Gross UnrealizedFair
Value		Yield
 GainsLosses
 ($ in thousands)
Available-for-sale securities
U.S. government and agency securities due
Within 1 year$1,687 $— $(29)$1,658 2.05 %
1 to 5 years545 — — 545 5.00 
5 to 10 years158,026 162 (295)157,893 4.95 
Over 10 years75,887 163 (227)75,823 5.52 
Asset-backed securities
Within 1 year10,492 — (163)10,329 5.12 
5 to 10 years3,945 7 — 3,952 5.27 
Over 10 years491,734 1,702 (1,383)492,053 5.36 
Corporate debt securities due
1 to 5 years32,821 — (2,047)30,774 4.95 
5 to 10 years128,015 314 (6,566)121,763 4.37 
Municipal bonds due
5 to 10 years25,659 250 (179)25,730 5.71 
Over 10 years9,754 — (226)9,528 4.57 
Mortgage-backed securities
Agency pass-through certificates2,603,873 38,399 (39,119)2,603,153 3.83 
3,542,438 40,997 (50,234)3,533,201 4.17 
Held-to-maturity securities
Mortgage-backed securities
Agency pass-through certificates645,802 4,073 (37,136)612,739 3.85 
$4,188,240 $45,070 $(87,370)$4,145,940 4.12 %
Schedule of Debt Securities, Available-for-Sale
The following tables show the gross unrealized losses and fair value of securities as of March 31, 2026 and September 30, 2025, by length of time that individual securities in each category have been in a continuous loss position. There were 274 and 213 securities with an unrealized loss as of March 31, 2026 and September 30, 2025, respectively.
 
March 31, 2026Less than 12 months12 months or moreTotal
 Unrealized
Gross Losses		Fair
Value		Unrealized
Gross Losses		Fair
Value		Unrealized
Gross Losses		Fair
Value
 (In thousands)
Available-for-sale securities
Corporate debt securities$— $— $(9,092)$121,148 $(9,092)$121,148 
Municipal bonds(100)19,900 (535)14,843 (635)34,743 
U.S. government and agency securities(94)14,955 (392)52,602 (486)67,557 
Asset-backed securities(160)38,933 (1,714)156,321 (1,874)195,254 
Mortgage-backed securities(8,208)966,835 (35,855)597,432 (44,063)1,564,267 
(8,562)1,040,623 (47,588)942,346 (56,150)1,982,969 
Held-to-maturity securities
Mortgage-backed securities(1,384)167,317 (35,239)297,402 (36,623)464,719 
$(9,946)$1,207,940 $(82,827)$1,239,748 $(92,773)$2,447,688 

September 30, 2025Less than 12 months12 months or moreTotal
 Unrealized
Gross Losses		Fair
Value		Unrealized
Gross Losses		Fair
Value		Unrealized
Gross Losses		Fair
Value
 (In thousands)
Available-for-sale securities
Corporate debt securities$(119)$19,881 $(8,495)$102,342 $(8,614)$122,223 
Municipal bonds due— — (405)15,008 (405)15,008 
U.S. government and agency securities(483)143,444 (127)35,211 (610)178,655 
Asset-backed securities(62)34,932 (1,424)135,315 (1,486)170,247 
Mortgage-backed securities(782)81,025 (38,337)653,800 (39,119)734,825 
(1,446)279,282 (48,788)941,676 (50,234)1,220,958 
Held-to-maturity securities
Mortgage-backed securities— — (37,136)310,597 (37,136)310,597 
$(1,446)$279,282 $(85,924)$1,252,273 $(87,370)$1,531,555