CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) - USD ($)	9 Months Ended
	Jun. 30, 2024	Jun. 30, 2023
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 138,901,000	$ 207,218,000
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization, accretion and other, net	194,150,000	15,667,000
Stock-based compensation expense	7,437,000	5,923,000
Provision (release) for credit losses	17,500,000	15,000,000
Loss (gain) on sale of investment securities	(250,000)	(3,000)
Gain on settlements of bank owned life insurance	0	(821,000)
Net realized (gain) loss on sales of premises, equipment, and real estate owned	(2,531,000)	(1,033,000)
Impairment loss on premises and equipment	0	6,000
Decrease (increase) in accrued interest receivable	9,290,000	(18,059,000)
Decrease (increase) in federal and state income tax receivable	9,246,000	0
Decrease (increase) in cash surrender value of bank owned life insurance	(5,119,000)	(4,409,000)
Decrease (increase) in other assets	42,415,000	(50,642,000)
Increase (decrease) in federal and state income tax liabilities	0	(674,000)
Increase (decrease) in accrued expenses and other liabilities	(68,427,000)	(37,095,000)
Net cash provided by (used in) operating activities	342,612,000	131,078,000
CASH FLOWS FROM INVESTING ACTIVITIES
Origination of loans and principal repayments, net	(447,832,000)	(1,208,282,000)
Loans purchased	0	(79,965,000)
Loans held for sale	0	0
FHLB stock purchased	(517,575,000)	(510,805,000)
FHLB stock redeemed	608,775,000	475,003,000
Available-for-sale securities purchased	(321,308,000)	(317,027,000)
Principal payments and maturities of available-for-sale securities	270,178,000	339,604,000
Proceeds from sales of available-for-sale securities	179,215,000	94,000
Held-to-maturity securities purchased	(47,092,000)	0
Principal payments and maturities of held-to-maturity securities	25,503,000	28,895,000
Proceeds from sales of real estate owned	6,271,000	2,715,000
Proceeds from settlement of bank owned life insurance	0	1,809,000
Purchase of strategic investments	(4,097,000)	(7,500,000)
Net cash received (paid) in business combinations	623,583,000	(785,000)
Proceeds from sales of loans	2,564,791,000	0
Proceeds from sales of premises and equipment	1,341,000	947,000
Premises and equipment purchased and REO improvements	(17,482,000)	(11,217,000)
Net cash provided by (used in) investing activities	2,924,271,000	(1,286,514,000)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase (decrease) in customer accounts	(517,961,000)	90,854,000
Proceeds from borrowings	15,936,735,000	13,575,000,000
Repayments of borrowings	(17,072,226,000)	(11,950,000,000)
Proceeds from stock-based awards	2,488,000	1,039,000
Dividends paid on common stock	(53,404,000)	(47,826,000)
Dividends paid on preferred stock	(10,969,000)	(10,968,000)
Proceeds from employee stock purchase	780,000	0
Treasury stock purchased	(26,819,000)	(30,450,000)
Increase (decrease) in advances payments by borrowers for taxes and insurance	(13,652,000)	(16,535,000)
Net cash provided by (used in) financing activities	(1,755,028,000)	1,611,114,000
Increase (decrease) in cash and cash equivalents	1,511,855,000	455,678,000
Cash, cash equivalents and restricted cash at beginning of period	980,649,000	683,965,000
Cash, cash equivalents and restricted cash at end of period	2,492,504,000	1,139,643,000
Non-cash investing activities
Real estate acquired through foreclosure	0	121,000
Non-cash financing activities
Preferred stock dividend payable	3,656,000	3,656,000
Cash paid (received) during the period for
Interest	534,614,000	243,465,000
Income tax	14,065,000	47,251,000
The following summarizes the non-cash activities related to acquisitions
Fair value of assets and intangibles acquired	7,676,486,000	0
Fair value of liabilities assumed	(7,316,542,000)	0
Net fair value of assets (liabilities)	$ 359,944,000	$ 0