Note 13 - Stock Option Plans - Summary of Outstanding Options (Details) - $ / shares	3 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Options Outstanding, Number of Shares Outstanding (in shares)	670,167	722,567	728,533	728,867
Options Outstanding, Weighted Average Remaining Contractual Life (Year)	2 years 255 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 8.19	$ 8.18	$ 8.17	$ 8.17
Options Exercisable, Number of Shares Exercisable (in shares)	670,167		728,533
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 8.19		$ 8.17
Range One [Member]
Range of Exercise Price, Lower (in dollars per share)	5.7501
Range of Exercise Price, Upper (in dollars per share)	$ 8.625
Options Outstanding, Number of Shares Outstanding (in shares)	560,667
Options Outstanding, Weighted Average Remaining Contractual Life (Year)	2 years 255 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 7.96
Options Exercisable, Number of Shares Exercisable (in shares)	560,667
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 7.96
Range Two [Member]
Range of Exercise Price, Lower (in dollars per share)	8.6251
Range of Exercise Price, Upper (in dollars per share)	$ 11.50
Options Outstanding, Number of Shares Outstanding (in shares)	109,500
Options Outstanding, Weighted Average Remaining Contractual Life (Year)	3 years 36 days
Options Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 9.37
Options Exercisable, Number of Shares Exercisable (in shares)	109,500
Options Exercisable, Weighted Average Exercise Price (in dollars per share)	$ 9.37