Note 3 - Income Taxes - Deferred Income Taxes (Details) - USD ($)	Sep. 30, 2019	Sep. 30, 2018
Deferred tax assets attributable to:
Accrued liabilities, including supplemental compensation and vacation pay accrual	$ 178,000	$ (106,000)
Impairment losses on investments	2,201,000	2,215,000
Bad debt reserves not yet deductible	41,000	42,000
Depreciation and amortization	3,999,000	4,446,000
Deferred revenues	885,000	745,000
Goodwill	677,000
Net operating losses	5,195,000	4,643,000
Credits and other	456,000	455,000
Total deferred tax assets	13,632,000	12,440,000
Deferred tax liabilities attributable to:
Unrealized gains on investments	(37,241,000)	(42,151,000)
Goodwill		(290,000)
Total deferred tax liabilities	(37,241,000)	(42,441,000)
Net deferred income taxes	$ (23,609,000)	$ (30,001,000)