Note 9 - Fair Value of Assets and Liabilities - Carrying Values and Estimated Fair Values of Financial Assets and Liabilities (Details) - USD ($)	Sep. 30, 2020		Sep. 30, 2019
Reported Value Measurement [Member]
Receivables from broker-dealers and clearing organizations	$ 3,367,000		$ 3,490,000
Forgivable loans receivable	4,269,000		1,834,000
Other Receivables, Net	12,394,000		5,672,000
Assets, Fair Value Disclosure	48,043,000		41,875,000
Accrued commissions and payroll payable	15,445,000		18,590,000
Accounts payable and accrued expenses	9,656,000	[1]	8,643,000	[2]
Nonfinancial Liabilities Fair Value Disclosure, Total	25,101,000		27,233,000
Estimate of Fair Value Measurement [Member]
Receivables from broker-dealers and clearing organizations	3,367,000		3,490,000
Forgivable loans receivable	4,269,000		1,834,000
Other Receivables, Net	12,394,000		5,672,000
Assets, Fair Value Disclosure	48,043,000		41,875,000
Accrued commissions and payroll payable	15,445,000		18,590,000
Accounts payable and accrued expenses	9,656,000	[1]	8,643,000	[2]
Nonfinancial Liabilities Fair Value Disclosure, Total	25,101,000		27,233,000
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Receivables from broker-dealers and clearing organizations
Forgivable loans receivable
Other Receivables, Net
Assets, Fair Value Disclosure	28,013,000		30,879,000
Accrued commissions and payroll payable
Accounts payable and accrued expenses		[1]		[2]
Nonfinancial Liabilities Fair Value Disclosure, Total
Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Receivables from broker-dealers and clearing organizations	3,367,000		3,490,000
Forgivable loans receivable	4,269,000		1,834,000
Other Receivables, Net	12,394,000		5,672,000
Assets, Fair Value Disclosure	20,030,000		10,996,000
Accrued commissions and payroll payable	15,445,000		18,590,000
Accounts payable and accrued expenses	9,656,000	[1]	8,643,000	[2]
Nonfinancial Liabilities Fair Value Disclosure, Total	25,101,000		27,233,000
Cash [Member] | Reported Value Measurement [Member]
Cash and cash equivalents	27,327,000		30,443,000
Cash [Member] | Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	27,327,000		30,443,000
Cash [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	27,327,000		30,443,000
Cash [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents
Interest-bearing Deposits [Member] | Reported Value Measurement [Member]
Cash and cash equivalents	686,000		436,000
Interest-bearing Deposits [Member] | Estimate of Fair Value Measurement [Member]
Cash and cash equivalents	686,000		436,000
Interest-bearing Deposits [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	686,000		436,000
Interest-bearing Deposits [Member] | Estimate of Fair Value Measurement [Member] | Fair Value, Inputs, Level 2 [Member]
Cash and cash equivalents

[1] Excludes contingent consideration liabilities of $1,620,000.

[2] Excludes contingent consideration liabilities of $744,000.