Registration of securities issued in business combination transactions

STOCKHOLDER'S EQUITY (Q3) (Details)

v3.21.4
STOCKHOLDER'S EQUITY (Q3) (Details)
9 Months Ended
Sep. 30, 2021
Vote
$ / shares
shares
Dec. 31, 2020
$ / shares
shares
Jan. 30, 2020
$ / shares
shares
Dec. 31, 2019
$ / shares
shares
Class of Stock [Line Items]        
Preferred stock, shares authorized 1,000,000 1,000,000 1,000,000 1,000,000
Preferred stock, par value | $ / shares $ 0.0001 $ 0.0001 $ 0.0001 $ 0.0001
Preferred stock, shares issued 0 0   0
Preferred stock, shares outstanding 0 0   0
Class A common stock subject to possible redemption, shares   23,000,000   0
Percentage of common stock outstanding for conversion basis 20.00%      
Class A Common Stock        
Class of Stock [Line Items]        
Common stock, shares authorized 100,000,000 100,000,000 100,000,000 100,000,000
Common stock, par value | $ / shares   $ 0.0001 $ 0.0001 $ 0.0001
Number of votes per share of common stock | Vote 1      
Common stock, shares outstanding 650,000 650,000    
Class A common stock subject to possible redemption, shares 23,000,000 23,000,000    
Class B Common Stock        
Class of Stock [Line Items]        
Common stock, shares authorized 10,000,000 10,000,000 10,000,000 10,000,000
Common stock, par value | $ / shares $ 0.0001 $ 0.0001 $ 0.0001 $ 0.0001
Number of votes per share of common stock | Vote 1      
Common stock, shares issued 5,750,000 5,750,000    
Common stock, shares outstanding 5,750,000 5,750,000