v3.26.3
Background and Basis of Presentation - Additional Information (Detail)
shares in Millions, $ in Millions
 3 Months Ended 6 Months Ended 9 Months Ended
Jul. 01, 2026
USD ($)
Sep. 30, 2026
USD ($)
Customer
shares
Sep. 30, 2025
USD ($)
Customer
shares
Jun. 30, 2025
Sep. 30, 2026
USD ($)
Customer
shares
Sep. 30, 2025
USD ($)
Customer
shares
Jan. 01, 2024
Organization Consolidation And Presentation Of Financial Statements [Line Items]              
Related party transactions   $ 0.0     $ 0.0    
Product warranty term         These product warranties extend over various periods, depending on the product subject to the warranty and the terms of the individual agreements.    
Intangible asset impairment charges, excluding goodwill   0.0 $ 0.0   $ 0.0 $ 0.0  
Goodwill impairment charges   0.0 0.0   0.0 0.0  
Income tax expense (benefit)   (20.0) 11.4   (42.3) (347.8)  
Tax Benefit   3.7     24.8    
Income Tax Expense Benefit Recognised   24.2     24.7 361.1  
Pre-tax net income (loss) for the period   $ 34.7 $ (7.5)   $ 55.1 $ (28.3)  
Statutory income tax rate   21.00%     21.00%    
Dilutive effect of equity-based awards | shares   2.2 0.0   5.6 10.2  
Cash proceeds from sale of segment         $ 12,409.8 $ 2,041.9  
ANS Reporting Unit [Member]              
Organization Consolidation And Presentation Of Financial Statements [Line Items]              
Percentage of exceeded carrying amount             9.00%
Belden Inc. [Member]              
Organization Consolidation And Presentation Of Financial Statements [Line Items]              
Cash proceeds from sale of segment $ 1,900.0            
Convertible Preferred Stock [Member]              
Organization Consolidation And Presentation Of Financial Statements [Line Items]              
Dilutive effect of equity-based awards | shares   0.0 10.3   1.5    
Stock Compensation Plan [Member]              
Organization Consolidation And Presentation Of Financial Statements [Line Items]              
Amount of outstanding equity based awards not included in computation of diluted earnings per share | shares   2.7 15.8   2.5    
Stock Compensation Plan [Member] | Convertible Preferred Stock [Member]              
Organization Consolidation And Presentation Of Financial Statements [Line Items]              
Amount of outstanding equity based awards not included in computation of diluted earnings per share | shares     45.9        
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Comcast Corporation [Member]              
Organization Consolidation And Presentation Of Financial Statements [Line Items]              
Concentration risk percentage   61.00% 60.00%   60.00% 49.00%  
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Charter Communications, Inc. [Member]              
Organization Consolidation And Presentation Of Financial Statements [Line Items]              
Concentration risk percentage       11.00%      
Customer Concentration Risk [Member] | Sales Revenue, Net [Member] | Other than Comcast and Charter [Member]              
Organization Consolidation And Presentation Of Financial Statements [Line Items]              
Direct customer accounted for 10% or more of the Company's accounts receivable and total net sales | Customer   0 0   0 0  
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Comcast Corporation [Member]              
Organization Consolidation And Presentation Of Financial Statements [Line Items]              
Concentration risk percentage         53.00%    
Customer Concentration Risk [Member] | Accounts Receivable [Member] | Other than Comcast and Charter [Member]              
Organization Consolidation And Presentation Of Financial Statements [Line Items]              
Concentration risk percentage         10.00%    
Direct customer accounted for 10% or more of the Company's accounts receivable and total net sales | Customer         0    
Customer Concentration Risk [Member] | Maximum [Member] | Sales Revenue, Net [Member] | Other than Comcast and Charter [Member]              
Organization Consolidation And Presentation Of Financial Statements [Line Items]              
Concentration risk percentage   10.00% 10.00%   10.00% 10.00%