Fair Value Of Financial Instruments (Schedule Of Carrying Amounts And Estimated Fair Values Of Financial Instruments) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Sep. 30, 2022	Jun. 30, 2022
Assets:
AFS Securities	$ 1,444,867	$ 1,563,307
Significant Unobservable Inputs (Level 3) [Member]
Assets:
Loans receivable	3,900		$ 4,300
Carrying Amount [Member]
Assets:
Cash and cash equivalents	329,409	49,194
AFS Securities	1,444,867	1,563,307
Loans receivable	7,963,360	7,464,208
FHLB stock	116,012	100,624
Interest rate swaps	12,369	12,547
Liabilities:
Deposits	6,092,840	6,194,866
Borrowings	2,986,162	2,132,154
Estimated Fair Value [Member]
Assets:
Cash and cash equivalents	329,409	49,194
AFS Securities	1,444,867	1,563,307
Loans receivable	7,547,542	6,889,211
FHLB stock	116,012	100,624
Interest rate swaps	12,369	12,547
Liabilities:
Deposits	6,041,135	6,124,835
Borrowings	2,913,752	1,910,779
Estimated Fair Value [Member] | Quoted Prices in Active Markets for Identical Assets (Level 1) [Member]
Assets:
Cash and cash equivalents	329,409	49,194
AFS Securities	0	0
Loans receivable	0	0
FHLB stock	116,012	100,624
Interest rate swaps	0	0
Liabilities:
Deposits	3,452,891	3,991,114
Borrowings	0	75,000
Estimated Fair Value [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Cash and cash equivalents	0	0
AFS Securities	1,444,867	1,563,307
Loans receivable	0	0
FHLB stock	0	0
Interest rate swaps	12,369	12,547
Liabilities:
Deposits	2,588,244	2,133,721
Borrowings	2,913,752	1,835,779
Estimated Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member]
Assets:
Cash and cash equivalents	0	0
AFS Securities	0	0
Loans receivable	7,547,542	6,889,211
FHLB stock	0	0
Interest rate swaps	0	0
Liabilities:
Deposits	0	0
Borrowings	$ 0	$ 0