Note 20 - Revenues From Contracts and Significant Customers - Disaggregation of Revenue (Details) - USD ($)	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Revenue from contracts with customers	$ 223,959,000	$ 207,884,000
Other revenue	5,916,000	5,057,000
Total Revenues	229,875,000	212,941,000
Commissions and Transfer Fees and Clearing Services [Member]
Revenue from contracts with customers	126,855,000	95,021,000
Banking [Member]
Revenue from contracts with customers	51,280,000	69,656,000
Investment Advice [Member]
Revenue from contracts with customers	35,676,000	34,400,000
Tax Preparation and Accounting [Member]
Revenue from contracts with customers	10,148,000	8,807,000
Corporate, Non-Segment [Member]
Revenue from contracts with customers
Other revenue	2,000
Total Revenues	2,000
Corporate, Non-Segment [Member] | Commissions and Transfer Fees and Clearing Services [Member]
Revenue from contracts with customers
Corporate, Non-Segment [Member] | Banking [Member]
Revenue from contracts with customers
Corporate, Non-Segment [Member] | Investment Advice [Member]
Revenue from contracts with customers
Corporate, Non-Segment [Member] | Tax Preparation and Accounting [Member]
Revenue from contracts with customers
Brokerage and Advisory Services [Member] | Operating Segments [Member]
Revenue from contracts with customers	213,811,000	199,077,000
Other revenue	5,913,000	5,057,000
Total Revenues	219,724,000	204,134,000
Brokerage and Advisory Services [Member] | Operating Segments [Member] | Commissions and Transfer Fees and Clearing Services [Member]
Revenue from contracts with customers	126,855,000	95,021,000
Brokerage and Advisory Services [Member] | Operating Segments [Member] | Banking [Member]
Revenue from contracts with customers	51,280,000	69,656,000
Brokerage and Advisory Services [Member] | Operating Segments [Member] | Investment Advice [Member]
Revenue from contracts with customers	35,676,000	34,400,000
Brokerage and Advisory Services [Member] | Operating Segments [Member] | Tax Preparation and Accounting [Member]
Revenue from contracts with customers
Tax and Accounting Services [Member] | Operating Segments [Member]
Revenue from contracts with customers	10,148,000	8,807,000
Other revenue	1,000
Total Revenues	10,149,000	8,807,000
Tax and Accounting Services [Member] | Operating Segments [Member] | Commissions and Transfer Fees and Clearing Services [Member]
Revenue from contracts with customers
Tax and Accounting Services [Member] | Operating Segments [Member] | Banking [Member]
Revenue from contracts with customers
Tax and Accounting Services [Member] | Operating Segments [Member] | Investment Advice [Member]
Revenue from contracts with customers
Tax and Accounting Services [Member] | Operating Segments [Member] | Tax Preparation and Accounting [Member]
Revenue from contracts with customers	$ 10,148,000	$ 8,807,000