Annual report pursuant to Section 13 and 15(d)

Variable Interest Entity - Additional Information (Detail)

v3.21.4
Variable Interest Entity - Additional Information (Detail) - USD ($)
Jun. 14, 2021
Sep. 30, 2021
Sep. 30, 2020
Nov. 01, 2019
Sep. 30, 2019
Variable Interest Entity [Line Items]          
Goodwill   $ 41,471,000 $ 37,754,000 $ 807,000 $ 36,947,000
Purchase Agreement          
Variable Interest Entity [Line Items]          
Percentage of units acquired in exchange for other consideration 24.90%        
Initial payment to the seller $ 1,700,000        
Non-refundable deposit to the seller $ 4,200,000        
Percentage of remaining units deposited into escrow with the seller legal counsel 75.10%        
Additional amount paid to the seller upon FINRA's approval $ 1,000,000.0        
Amount already paid to the seller upon FINRA's approval $ 200,000        
Salomon Whitney LLC          
Variable Interest Entity [Line Items]          
Percentage of outstanding membership interests acquired 100.00%        
Payment to acquire business $ 7,000,000.0        
Goodwill $ 3,717,000 $ 3,700,000