Registration of securities issued in business combination transactions

RELATED PARTY TRANSACTIONS (FY) (Details)

v3.21.4
RELATED PARTY TRANSACTIONS (FY) (Details) - USD ($)
3 Months Ended 9 Months Ended 12 Months Ended
Oct. 31, 2020
Aug. 14, 2020
Feb. 06, 2020
Jan. 10, 2020
Sep. 30, 2021
Sep. 30, 2020
Mar. 31, 2020
Sep. 30, 2021
Sep. 30, 2020
Dec. 31, 2020
Aug. 24, 2020
Related Party Transaction [Line Items]                      
Aggregate purchase price             $ 25,000     $ 25,000  
General and administrative services expense per month   $ 15,000                  
Related party transaction Converted notes Price per share upon consummation of a Business Combination               $ 10.00   $ 10.00  
Unsecured promissory note                      
Related Party Transaction [Line Items]                      
Borrowings principal amount       $ 300,000              
Due to related parties                     $ 140,671
Maximum                      
Related Party Transaction [Line Items]                      
Related party transaction Converted notes upon consummation of a Business Combination               $ 1,000,000.0   $ 1,000,000  
Sponsor                      
Related Party Transaction [Line Items]                      
Number of shares issued     5,750,000                
Share dividend     0.15                
Aggregate number of shares owned     5,750,000                
Shares subject to forfeiture                     750,000
Percentage of issued and outstanding shares after the Initial Public Offering collectively held by initial stockholders 22.03%                    
Stock price trigger to transfer, assign or sell any shares or warrants of the company, after the completion of the initial business combination (in dollars per share)       $ 12.00              
Threshold trading days for transfer, assign or sale of shares or warrants, after the completion of the initial business combination       20 days              
Threshold consecutive trading days for transfer, assign or sale of shares or warrants, after the completion of the initial business combination       30 days              
Sponsor | Maximum                      
Related Party Transaction [Line Items]                      
Shares subject to forfeiture       750,000              
Sponsor | Class B Common Stock                      
Related Party Transaction [Line Items]                      
Number of shares issued       5,000,000              
Aggregate purchase price       $ 25,000              
Accounts Payable and Accrued Liabilities                      
Related Party Transaction [Line Items]                      
Fees for administrative support         $ 45,000 $ 30,000   $ 135,000 $ 30,000 $ 66,774  
Founder share [Member] | Sponsor | Class B Common Stock                      
Related Party Transaction [Line Items]                      
Threshold consecutive trading days for transfer, assign or sale of shares or warrants, after the completion of the initial business combination       30 days