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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
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Amortized cost excluding accrued interest, before allowance for credit loss, fee, and loan in process, of financing receivable. Excludes net investment in lease.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
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Amount of unamortized loan commitment, origination, and other costs (fees) on financing receivable recognized as adjustment to yield. Excludes financing receivable covered under loss sharing agreement.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 310
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Amount of unamortized purchase premium (discount) on financing receivable. Excludes financing receivable covered under loss sharing agreement.

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Loans Receivable And Allowance For Credit Losses (Summary Of Loans Receivable) (Details) - USD ($) $ in Thousands	Mar. 31, 2026	Dec. 31, 2025	Sep. 30, 2025	Mar. 31, 2025	Dec. 31, 2024	Sep. 30, 2024
Loans Receivable [Line Items]
Loans receivable, gross	$ 8,139,296		$ 8,133,875
ACL	26,599	$ 24,572	24,039	$ 23,970	$ 24,997	$ 23,035
Deferred loan fees/discounts	30,087		31,268
Premiums/deferred costs	(31,595)		(33,393)
Loans receivable, net	8,114,205		8,111,961
One- to Four-Family Segment [Member]
Loans Receivable [Line Items]
Loans receivable, gross	5,707,809		5,904,635
ACL	2,663	2,842	3,046	3,562	3,757	3,673
One- to Four-Family Segment [Member] \| Originated [Member]
Loans Receivable [Line Items]
Loans receivable, gross	3,676,252		3,774,134
One- to Four-Family Segment [Member] \| Correspondent Purchased [Member]
Loans Receivable [Line Items]
Loans receivable, gross	1,905,759		2,000,216
One- to Four-Family Segment [Member] \| Bulk Purchased [Member]
Loans Receivable [Line Items]
Loans receivable, gross	109,675		114,231
One- to Four-Family Segment [Member] \| Construction [Member]
Loans Receivable [Line Items]
Loans receivable, gross	16,123		16,054
Commercial Segment [Member]
Loans Receivable [Line Items]
Loans receivable, gross	2,317,746		2,115,995
ACL	23,735	21,522	20,776	20,176	20,999	19,154
Commercial Segment [Member] \| Construction [Member]
Loans Receivable [Line Items]
Loans receivable, gross	189,251		195,886
Commercial Segment [Member] \| Commercial Real Estate [Member]
Loans Receivable [Line Items]
Loans receivable, gross	1,896,313		1,709,990
ACL	21,689	19,696	18,277	19,005	19,790	17,968
Commercial Segment [Member] \| Commercial and Industrial [Member]
Loans Receivable [Line Items]
Loans receivable, gross	232,182		210,119
ACL	2,046	1,826	2,499	1,171	1,209	1,186
Consumer Segment [Member]
Loans Receivable [Line Items]
Loans receivable, gross	113,741		113,245
ACL	201	$ 208	217	$ 232	$ 241	$ 208
Consumer Segment [Member] \| Home Equity [Member]
Loans Receivable [Line Items]
Loans receivable, gross	106,414		104,809
Consumer Segment [Member] \| Other [Member]
Loans Receivable [Line Items]
Loans receivable, gross	$ 7,327		$ 8,436