Note 2 - Summary of Significant Accounting Policies (Details Textual) - USD ($)		12 Months Ended
	Dec. 24, 2020	Sep. 30, 2020	Sep. 30, 2019
Variable Interest Entity, Distribution Threshold		100.00%
Investment Banking, Advisory, Brokerage, and Underwriting Fees and Commissions, Total		$ 21,404,000	$ 34,184,000
Revenue from Contract with Customer, Excluding Assessed Tax, Total		223,959,000	207,884,000
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)		(2,895,000)	(2,820,000)
Unrecognized Tax Benefits, Ending Balance		$ 0	$ 0
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount (in shares)		9,166,422	9,321,747
Deferred Clearing Rebates, Revenue Recognized		$ 143,000	$ 143,000
Deferred Clearing Rebates		107,000	250,000
Deferred Marketing Rebates, Revenue Recognized		67,000
Deferred Marketing Rebates		50,000	117,000
Reimbursement Revenue 1		7,889,000	7,422,000
Banking [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total		51,280,000	69,656,000
Investment Advice [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total		35,676,000	34,400,000
The Funds [Member]
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss)			(2,389,000)
Unrecognized Carried Interest		8,086,000
Unrecognized Carried Interest, Compensation Expense		5,651,000
The Funds [Member] | Subsequent Event [Member]
Unrecognized Carried Interest	$ 49,776,000
Unrecognized Carried Interest, Compensation Expense	$ 34,412,000
The Funds [Member] | Carried Interest [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total		$ 0	15,872,000
The Funds [Member] | Banking [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total			5,403,000
The Funds [Member] | Investment Advice [Member]
Revenue from Contract with Customer, Excluding Assessed Tax, Total			$ 10,469,000
Minimum [Member]
Variable Interest Entity, Timing Of Liquidity Event For New Opportunities (Year)		1 year
Variable Interest Entity, Cash Fee Received, Percent		7.00%
Variable Interest Entity, Interest Received, Percent		8.00%
Maximum [Member]
Variable Interest Entity, Timing Of Liquidity Event For New Opportunities (Year)		5 years
Variable Interest Entity, Cash Fee Received, Percent		10.00%
Variable Interest Entity, Interest Received, Percent		15.00%
Financing Receivable, Interest Rate			9.00%