Consolidated Statements Of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
INTEREST AND DIVIDEND INCOME:
Loans receivable	$ 66,652	$ 71,434	$ 206,179	$ 213,863
Mortgage-backed securities ("MBS")	5,616	6,613	17,584	19,437
FHLB stock	1,207	1,865	4,747	5,667
Investment securities	847	1,835	3,736	4,781
Cash and cash equivalents	59	464	1,126	2,921
Total interest and dividend income	74,381	82,211	233,372	246,669
INTEREST EXPENSE:
Deposits	16,533	16,909	52,299	48,730
Borrowings	11,561	13,621	37,421	41,360
Total interest expense	28,094	30,530	89,720	90,090
NET INTEREST INCOME	46,287	51,681	143,652	156,579
PROVISION FOR CREDIT LOSSES	0	450	22,300	450
NET INTEREST INCOME AFTER PROVISION FOR CREDIT LOSSES	46,287	51,231	121,352	156,129
NON-INTEREST INCOME:
Revenue from contracts with customers			10,900	12,400
Other non-interest income	1,229	1,638	4,468	4,446
Total non-interest income	4,439	5,674	14,614	16,099
NON-INTEREST EXPENSE:
Salaries and employee benefits	13,059	13,454	39,765	39,205
Information technology and related expense	4,285	4,652	12,694	13,535
Occupancy, net	3,556	3,224	10,212	9,768
Regulatory and outside services	1,548	1,425	4,188	4,247
Advertising and promotional	1,004	1,447	3,773	3,597
Deposit and loan transaction costs	697	681	2,086	1,882
Office supplies and related expense	475	689	1,586	1,884
Federal insurance premium	287	600	287	1,787
Other non-interest expense	1,253	1,519	4,237	4,709
Total non-interest expense	26,164	27,691	78,828	80,614
INCOME BEFORE INCOME TAX EXPENSE	24,562	29,214	57,138	91,614
INCOME TAX EXPENSE	5,088	6,317	10,877	19,780
NET INCOME	$ 19,474	$ 22,897	$ 46,261	$ 71,834
Basic earnings per share ("EPS")	$ 0.14	$ 0.17	$ 0.34	$ 0.52
Diluted EPS	$ 0.14	$ 0.17	$ 0.34	$ 0.52
Basic weighted average common shares	138,018,052	137,720,480	137,961,231	137,635,099
Diluted weighted average common shares	138,018,052	137,787,528	137,992,978	137,690,434
Deposit service fees [Member]
NON-INTEREST INCOME:
Revenue from contracts with customers	$ 2,539	$ 3,131	$ 8,384	$ 9,581
Insurance commissions [Member]
NON-INTEREST INCOME:
Revenue from contracts with customers	$ 671	$ 905	$ 1,762	$ 2,072