CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 145,443	$ 99,640
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization, accretion and other, net	864	31,110
Stock-based compensation expense	4,027	3,846
Provision (release) for credit losses	6,000	0
Loss (gain) on sale of investment securities	0	(81)
Gain on bank owned life insurance	(821)	0
Net realized (gain) loss on sales of premises, equipment, and real estate owned	(130)	74
Impairment loss on premises and equipment	6	0
Decrease (increase) in accrued interest receivable	(15,197)	(804)
Decrease (increase) in federal and state income tax receivable	0	(450)
Decrease (increase) in cash surrender value of bank owned life insurance	(2,898)	(2,761)
Decrease (increase) in other assets	12,840	(38,217)
Increase (decrease) in federal and state income tax liabilities	1,961	0
Increase (decrease) in accrued expenses and other liabilities	(41,170)	(9,107)
Net cash provided by (used in) operating activities	110,925	83,250
CASH FLOWS FROM INVESTING ACTIVITIES
Origination of loans and principal repayments, net	(1,076,495)	(754,450)
Loans purchased	(79,965)	(525,825)
FHLB stock purchased	(372,005)	(108,000)
FHLB & FRB stock redeemed	320,000	131,990
Available-for-sale securities purchased	(115,931)	(124,651)
Principal payments and maturities of available-for-sale securities	178,589	287,775
Proceeds from sales of available-for-sale securities	0	4,510
Principal payments and maturities of held-to-maturity securities	17,936	63,214
Proceeds from sales of real estate owned	810	3,175
Proceeds from settlement of bank owned life insurance	1,809	0
Equity securities purchased	(7,434)	0
Proceeds from sales of premises and equipment	664	41
Premises and equipment purchased and REO improvements	(5,009)	(5,738)
Net cash provided by (used in) investing activities	(1,137,031)	(1,027,959)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase (decrease) in customer accounts	(168,622)	848,536
Proceeds from borrowings	9,675,000	2,700,000
Repayments of borrowings	(8,000,000)	(2,700,000)
Proceeds from stock-based awards	1,023	1,361
Dividends paid on common stock	(31,828)	(30,456)
Dividends paid on preferred stock	(7,313)	(7,312)
Treasury stock purchased	(1,836)	(3,135)
Increase (decrease) in advances payments by borrowers for taxes and insurance	(5,739)	(7,590)
Net cash provided by (used in) financing activities	1,460,685	801,404
Increase (decrease) in cash and cash equivalents	434,579	(143,305)
Cash, cash equivalents and restricted cash at beginning of period	683,965	2,090,809
Cash, cash equivalents and restricted cash at end of period	1,118,544	1,947,504
Non-cash investing activities
Real estate acquired through foreclosure	121	0
Other personal property acquired through foreclosure	0	422
Non-cash financing activities
Preferred stock dividend payable	3,656	3,656
Cash paid (received) during the period for
Interest	135,037	25,979
Income taxes	$ 30,951	$ 19,001