Consolidated Statements Of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
INTEREST AND DIVIDEND INCOME:
Loans receivable	$ 71,434	$ 64,893	$ 213,863	$ 193,276
Mortgage-backed securities (MBS)	6,613	5,921	19,437	16,563
FHLB stock	1,865	2,819	5,667	9,115
Investment securities	1,835	1,307	4,781	3,395
Cash and cash equivalents	464	7,221	2,921	22,230
Total interest and dividend income	82,211	82,161	246,669	244,579
INTEREST EXPENSE:
Deposits	16,909	13,587	48,730	38,028
FHLB borrowings	12,981	18,501	39,036	55,190
Other borrowings	640	640	2,324	2,665
Total interest expense	30,530	32,728	90,090	95,883
NET INTEREST INCOME	51,681	49,433	156,579	148,696
PROVISION FOR CREDIT LOSSES	450	0	450	0
NET INTEREST INCOME AFTER PROVISION FOR CREDIT LOSSES	51,231	49,433	156,129	148,696
NON-INTEREST INCOME:
Deposit service fees			12,400
Income from bank-owned life insurance (BOLI)	590	510	1,812	1,320
Other non-interest income	1,953	999	4,706	3,345
Total non-interest income	5,674	5,424	16,099	16,215
NON-INTEREST EXPENSE:
Salaries and employee benefits	13,454	11,936	39,205	33,631
Information technology and related expense	4,652	3,363	13,535	10,316
Occupancy, net	3,224	2,787	9,768	8,391
Regulatory and outside services	1,425	1,628	4,247	3,919
Advertising and promotional	1,447	1,490	3,597	3,512
Office supplies and related expense	689	455	1,884	1,339
Deposit and loan transaction costs	681	1,437	1,882	4,157
Federal insurance premium	600	813	1,787	2,512
Other non-interest expense	1,519	602	4,709	2,368
Total non-interest expense	27,691	24,511	80,614	70,145
INCOME BEFORE INCOME TAX EXPENSE	29,214	30,346	91,614	94,766
INCOME TAX EXPENSE	6,317	7,974	19,780	17,228
NET INCOME	$ 22,897	$ 22,372	$ 71,834	$ 77,538
Basic earnings per share (EPS)	$ 0.17	$ 0.17	$ 0.52	$ 0.58
Diluted EPS	$ 0.17	$ 0.17	$ 0.52	$ 0.58
Basic weighted average common shares	137,720,480	134,484,240	137,635,099	134,428,280
Diluted weighted average common shares	137,787,528	134,529,953	137,690,434	134,490,555
Deposit Account [Member]
NON-INTEREST INCOME:
Deposit service fees	$ 3,131	$ 3,915	$ 9,581	$ 11,550