v3.20.4
Cover Page - shares
 2 Months Ended
Sep. 30, 2020
Jan. 07, 2021
Document Information [Line Items]    
Document Type 10-Q  
Document Period End Date Sep. 30, 2020  
Amendment Flag false  
Document Fiscal Period Focus Q3  
Document Fiscal Year Focus 2020  
Entity Current Reporting Status No  
Entity Filer Category Non-accelerated Filer  
Entity Registrant Name Genesis Park Acquisition Corp.  
Entity Interactive Data Current Yes  
Current Fiscal Year End Date --12-31  
Entity Central Index Key 0001819810  
Entity Incorporation, State or Country Code KY  
Entity Address, State or Province TX  
Document Quarterly Report true  
Document Transition Report false  
Entity Shell Company true  
Entity Small Business true  
Entity Emerging Growth Company true  
Entity Ex Transition Period false  
Title of 12(b) Security Class A ordinary shares  
Trading Symbol GNPK  
Security Exchange Name NYSE  
Common Class A [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   16,377,622
Common Class B [Member]    
Document Information [Line Items]    
Entity Common Stock, Shares Outstanding   4,094,406
Capital Units [Member]    
Document Information [Line Items]    
Title of 12(b) Security Units  
Trading Symbol GNPK. U  
Security Exchange Name NYSE  
Warrant [Member]    
Document Information [Line Items]    
Title of 12(b) Security Warrants  
Trading Symbol GNPK WS  
Security Exchange Name NYSE