Segment Reporting (Financial Statements Information) (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Net interest income	$ 9,507	$ 7,532	$ 26,283	$ 21,708
Net gains on sales of loans, SBA	1,558	938	4,585	2,741
Noncash items:
Provision for loan losses	266	321	1,099	1,002
Depreciation and amortization	361	289	995	871
Income tax expense (benefit)	696	586	1,656	1,680
Segment profit	3,677	2,443	9,392	6,974
Segment assets	1,035,346	874,082	1,035,346	874,082
Core Banking Segment [Member]
Net interest income	8,688	6,993	24,182	20,454
Net gains on sales of loans, SBA	0	0	0	0
Noncash items:
Provision for loan losses	52	200	(86)	665
Depreciation and amortization	349	278	957	840
Income tax expense (benefit)	825	597	2,006	1,819
Segment profit	2,336	1,959	6,550	5,582
Segment assets	1,026,998	869,920	1,026,998	869,920
SBA Lending Segment [Member]
Net interest income	810	533	2,078	1,239
Net gains on sales of loans, SBA	1,558	938	4,585	2,741
Noncash items:
Provision for loan losses	214	121	1,185	337
Depreciation and amortization	12	11	38	31
Income tax expense (benefit)	0	0	0	0
Segment profit	1,166	405	2,559	1,046
Segment assets	64,206	45,900	64,206	45,900
Other Segment [Member]
Net interest income	9	6	23	15
Net gains on sales of loans, SBA	0	0	0	0
Noncash items:
Provision for loan losses	0	0	0	0
Depreciation and amortization	0	0	0	0
Income tax expense (benefit)	(129)	(11)	(350)	(139)
Segment profit	175	79	283	346
Segment assets	$ (55,858)	$ (41,738)	$ (55,858)	$ (41,738)