General form of registration statement for all companies including face-amount certificate companies

Related Party Transactions - Additional Information (Detail)

v3.21.2
Related Party Transactions - Additional Information (Detail) - USD ($)
9 Months Ended 12 Months Ended
Sep. 30, 2021
Dec. 31, 2020
Dec. 31, 2019
Former Co Founders [Member]      
Repayment of promissory notes to related party $ 2,500,000    
Former Co Founders [Member] | Interest [Member]      
Repayment of promissory notes to related party 25,000    
Blacksky Technology [Member]      
Interest paid   $ 0 $ 0
Interest payable to related parties 4,700,000    
Blacksky Technology [Member] | Two Thousand and Twenty One Bridge Financing [Member] | Debt First And Second Tranche [Member] | Two Thousand and Twenty One Bridge Notes [Member] | Intelsat And Sehwak [Member]      
Consent fees payable $ 2,500,000