Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock [Member]	Retained Earnings [Member]
Beginning balance at Sep. 30, 2016	$ 37,331	$ 13,279	$ 24,052
Beginning balance, Shares at Sep. 30, 2016		7,661,969
Net income	14,942		14,942
Dividends paid	(2,243)		(2,243)
Employee and director restricted stock vested	0	$ 0	0
Employee and director restricted stock vested, Shares		152,322
Repurchase of vested employee restricted stock for tax withholding	(653)	$ (489)	(164)
Repurchase of vested employee restricted stock for tax withholding, Shares		(39,820)
Shares issued for auto-investments pursuant to the 2015 and 2018 Dividend Reinvestment and Stock Purchase Plans	3	$ 3
Shares issued for auto-investments pursuant to the 2015 and 2018 Dividend Reinvestment and Stock Purchase Plans, Shares		183
Shares issued for dividend reinvestment pursuant to the 2015 and 2018 Dividend Reinvestment and Stock Purchase Plans	33	$ 33
Shares issued for dividend reinvestment pursuant to the 2015 and 2018 Dividend Reinvestment and Stock Purchase Plans, Shares		1,965
Stock-based compensation	2,118	$ 2,118
Adjustment for fractional shares paid in cash in connection with stock split	(1)	$ (1)
Adjustment for fractional shares paid in cash in connection with stock split, Shares		(56)
Ending balance at Sep. 30, 2017	51,530	$ 14,943	36,587
Ending balance, shares at Sep. 30, 2017		7,776,563
Net income	20,615		20,615
Dividends paid	(2,928)		(2,928)
Employee and director restricted stock vested	0	$ 0	0
Employee and director restricted stock vested, Shares		161,501
Repurchase of vested employee restricted stock for tax withholding	(660)	$ (583)	$ (77)
Repurchase of vested employee restricted stock for tax withholding, Shares		(44,507)
Shares issued for auto-investments pursuant to the 2015 and 2018 Dividend Reinvestment and Stock Purchase Plans	16	$ 16
Shares issued for auto-investments pursuant to the 2015 and 2018 Dividend Reinvestment and Stock Purchase Plans, Shares		873
Shares issued for dividend reinvestment pursuant to the 2015 and 2018 Dividend Reinvestment and Stock Purchase Plans	45	$ 45
Shares issued for dividend reinvestment pursuant to the 2015 and 2018 Dividend Reinvestment and Stock Purchase Plans, Shares		2,715
Stock-based compensation	2,413	$ 2,413
Employee restricted stock forfeiture	$ (51)	$ (51)
Employee restricted stock forfeiture,shares	0	0	0
Ending balance at Sep. 30, 2018	$ 70,980	$ 16,783	$ 54,197
Ending balance, shares at Sep. 30, 2018		7,897,145