Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock Outstanding [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Total
Balance (in shares)	22,373,382
Balance (in shares) at Sep. 30, 2018	22,373,382
Balance at Sep. 30, 2018	$ 23	$ 56,236	$ 91,507	$ (1,040)	$ 146,726
Net income			2,197		2,197
Share-based compensation (in shares)	18,928
Share-based compensation		101		144	245
Balance (in shares) at Dec. 31, 2018	22,392,310
Balance at Dec. 31, 2018	$ 23	56,337	93,704	(896)	149,168
Balance (in shares)	22,392,310
Balance (in shares) at Sep. 30, 2018	22,373,382
Balance at Sep. 30, 2018	$ 23	56,236	91,507	(1,040)	146,726
Net income					6,057
Balance (in shares) at Mar. 31, 2019	22,431,553
Balance at Mar. 31, 2019	$ 23	56,192	97,564	(598)	153,181
Balance (in shares)	22,431,553
Balance (in shares)	22,392,310
Balance (in shares) at Dec. 31, 2018	22,392,310
Balance at Dec. 31, 2018	$ 23	56,337	93,704	(896)	149,168
Net income			3,860		3,860
Share-based compensation (in shares)	39,243
Share-based compensation		(145)		298	153
Balance (in shares) at Mar. 31, 2019	22,431,553
Balance at Mar. 31, 2019	$ 23	56,192	97,564	(598)	153,181
Balance (in shares)	22,431,553
Balance (in shares)	22,431,553
Balance (in shares)	22,463,057
Balance (in shares) at Sep. 30, 2019	22,463,057
Balance at Sep. 30, 2019	$ 23	56,319	100,923	(359)	156,906
Net income			1,868		1,868
Cash dividends			(1,573)		(1,573)
Share-based compensation (in shares)	12,661
Share-based compensation		135		96	231
Topic 842 transition impact			1,660		1,660
Balance (in shares) at Dec. 31, 2019	22,475,718
Balance at Dec. 31, 2019	$ 23	56,454	102,878	(263)	159,092
Balance (in shares)	22,475,718
Balance (in shares) at Sep. 30, 2019	22,463,057
Balance at Sep. 30, 2019	$ 23	56,319	100,923	(359)	156,906
Net income					11,586
Balance (in shares) at Mar. 31, 2020	22,503,810
Balance at Mar. 31, 2020	$ 23	56,439	111,022	(49)	167,435
Balance (in shares)	22,503,810
Balance (in shares)	22,475,718
Balance (in shares) at Dec. 31, 2019	22,475,718
Balance at Dec. 31, 2019	$ 23	56,454	102,878	(263)	159,092
Net income			9,718		9,718
Cash dividends			(1,574)		(1,574)
Share-based compensation (in shares)	28,092
Share-based compensation		(15)		214	199
Balance (in shares) at Mar. 31, 2020	22,503,810
Balance at Mar. 31, 2020	$ 23	$ 56,439	$ 111,022	$ (49)	$ 167,435
Balance (in shares)	22,503,810
Balance (in shares)	22,503,810