CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2023	Mar. 31, 2022	Mar. 31, 2023	Mar. 31, 2022
INTEREST INCOME
Loans receivable	$ 222,957	$ 139,260	$ 426,903	$ 277,769
Mortgage-backed securities	10,422	4,659	21,035	9,451
Investment securities and cash equivalents	21,967	6,919	40,827	14,058
Interest income	255,346	150,838	488,765	301,278
INTEREST EXPENSE
Customer accounts	52,123	8,225	83,769	16,686
Borrowings	28,185	7,525	47,159	15,368
Interest expense	80,308	15,750	130,928	32,054
Net interest income	175,038	135,088	357,837	269,224
Provision (release) for credit losses	3,500	(500)	6,000	0
Net interest income after provision (release)	171,538	135,588	351,837	269,224
OTHER INCOME
Gain (loss) on sale of investment securities	0	0	0	81
Gain (loss) on hedging derivatives	26	0	26	0
Loan fee income	$ 652	$ 2,475	$ 2,154	$ 4,396
Revenue, Product and Service [Extensible Enumeration]	Deposit Account [Member]	Deposit Account [Member]	Deposit Account [Member]	Deposit Account [Member]
Deposit fee income	$ 6,188	$ 6,282	$ 12,541	$ 12,725
Other income	3,206	6,902	9,375	17,138
Other income, total	10,072	15,659	24,096	34,340
OTHER EXPENSE
Compensation and benefits	51,444	47,115	100,514	94,540
Occupancy	10,918	11,788	21,020	21,878
FDIC insurance premiums	4,000	2,100	7,675	5,200
Product delivery	5,316	5,044	9,937	9,765
Information technology	12,785	11,722	25,114	23,143
Other expense	12,418	10,648	24,899	23,504
Other expense, total	96,881	88,417	189,159	178,030
Gain (loss) on real estate owned, net	(199)	129	(311)	691
Income before income taxes	84,530	62,959	186,463	126,225
Income tax expense	18,596	13,600	41,020	26,585
Net income	65,934	49,359	145,443	99,640
Dividends on preferred stock	3,656	3,656	7,312	7,312
Net income available to common shareholders	$ 62,278	$ 45,703	$ 138,131	$ 92,328
PER SHARE DATA
Basic earnings per common share (in dollars per share)	$ 0.95	$ 0.70	$ 2.11	$ 1.41
Diluted earnings per common share (in dollars per share)	0.95	0.70	2.11	1.41
Dividends paid on common stock per share (in dollars per share)	$ 0.25	$ 0.24	$ 0.49	$ 0.47
Basic weighted average number of shares outstanding (in shares)	65,511,131	65,301,171	65,425,623	65,253,991
Diluted weighted average number of shares outstanding (in shares)	65,551,185	65,445,206	65,510,275	65,397,601