Quarterly report pursuant to Section 13 or 15(d)

Nature of Operations - Additional Information (Detail)

v3.21.2
Nature of Operations - Additional Information (Detail)
3 Months Ended 9 Months Ended
Sep. 25, 2021
USD ($)
Number
Sep. 25, 2021
USD ($)
Sep. 26, 2020
USD ($)
Sep. 25, 2021
USD ($)
Segments
Sep. 26, 2020
USD ($)
Aug. 31, 2021
Aug. 18, 2021
Aug. 17, 2021
Jan. 18, 2021
Dec. 26, 2020
USD ($)
Jan. 02, 2020
Schedule of Equity Method Investments [Line Items]                      
Business Combination Percentage of Net Assets Acquired                 100.00%    
Number of reportable segments 2     2              
Assets $ 1,130,374,999 $ 1,130,374,999   $ 1,130,374,999           $ 873,478,745  
Revenue   187,789,925 $ 140,339,058 514,796,582 $ 400,382,475            
DBCI LLC [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Business acquisition percentage of voting interests acquired               100.00%      
Access Control Technologies LLC [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Business acquisition percentage of voting interests acquired           100.00%          
Janus Core [Member] | DBCI LLC [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Business acquisition percentage of voting interests acquired             100.00%        
Janus Core [Member] | Access Control Technologies LLC [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Business acquisition percentage of voting interests acquired           100.00%          
Foreign Locations [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Assets $ 56,439,000 56,439,000   56,439,000           $ 53,424,000  
Revenue   $ 17,824,000 $ 12,621,000 $ 48,729,000 $ 32,165,000            
Janus International Europe Holdings Ltd UK JIE [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Equity Method Investment, Ownership Percentage 100.00% 100.00%   100.00%              
Janus International Europe Holdings Ltd UK JIE [Member] | Active Supply Design CDM Ltd UKASD [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Equity Method Investment, Ownership Percentage 100.00% 100.00%   100.00%              
Janus International Europe Holdings Ltd UK JIE [Member] | Steel Storage Australia Asia Steel Storage [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Equity Method Investment, Ownership Percentage 100.00% 100.00%   100.00%              
Percentage Of Outstanding Shares Purchased                     100.00%
Janus Cob bHoldings LLC Cobb [Member] | Asta Industries Inc ASTA [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Equity Method Investment, Ownership Percentage 100.00% 100.00%   100.00%              
Janus Cob bHoldings LLC Cobb [Member] | Nok Inc NOKE [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Equity Method Investment, Ownership Percentage 100.00% 100.00%   100.00%              
Janus Cob bHoldings LLC Cobb [Member] | Betco Inc BETCO [Member]                      
Schedule of Equity Method Investments [Line Items]                      
Equity Method Investment, Ownership Percentage 100.00% 100.00%   100.00%