Registration of securities issued in business combination transactions

PRIVATE PLACEMENT (Q3) (Details)

v3.21.4
PRIVATE PLACEMENT (Q3) (Details) - USD ($)
3 Months Ended 12 Months Ended
Aug. 18, 2020
Mar. 31, 2020
Dec. 31, 2020
Sep. 30, 2021
Subsidiary, Sale of Stock [Line Items]        
Purchase price   $ 25,000 $ 25,000  
Private placement        
Subsidiary, Sale of Stock [Line Items]        
Issuance of Class B common stock to Sponsor (in shares) 650,000      
Purchase price per unit $ 10.00      
Purchase price $ 6,500,000      
Private placement | Class A Common Stock        
Subsidiary, Sale of Stock [Line Items]        
Warrants exercise price       $ 11.50