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Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Significant Accounting Policies [Line Items]        
Allowance for Doubtful Accounts $ 3.1 $ 2.4 $ 1.3 $ 1.3
Reserve for sale 4.4 3.7    
Interest on property plant and equipment,net 0.5 0.8    
Net of accumulated amortization 78.7 70.4    
Amortization of software cost 3.8 16.2 18.5  
Amortization expense for the deferred costs 38.8 32.2 26.2  
Research and Development Expense 39.6 34.1 29.6  
Advertising Expense $ 5.5 5.4 5.8  
Defined benefit plan expected long-term rate-of-return, description The long-term rate of return is estimated by considering historical returns and expected returns on current and projected asset allocations and is generally applied to a five-year average market value of assets.      
ASU 2018-14 [Member]        
Significant Accounting Policies [Line Items]        
Change in Accounting Principle, Accounting Standards Update, Adoption Date Jan. 01, 2020      
Change in Accounting Principle, Accounting Standards Update, Adopted [true false] true      
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false] true      
ASU 2016-13 [Member]        
Significant Accounting Policies [Line Items]        
Change in Accounting Principle, Accounting Standards Update, Adoption Date Jan. 01, 2020      
Change in Accounting Principle, Accounting Standards Update, Adopted [true false] true      
Change in Accounting Principle, Accounting Standards Update, Immaterial Effect [true false] true      
ASU 2016-02 [Member]        
Significant Accounting Policies [Line Items]        
Change in Accounting Principle, Accounting Standards Update, Adoption Date Jan. 01, 2019      
Change in Accounting Principle, Accounting Standards Update, Adopted [true false] true      
Defined Benefit Pension Plan [Member]        
Significant Accounting Policies [Line Items]        
Impact of change in discount rate of basis points 0.25%      
Impact of change in discount rate defined benefit plan liability $ 13.0      
Defined benefit plan pre-tax earnings $ 0.3      
Change in the assumption for the long-term rate of return on plan assets basis points 0.25%      
Change in the assumption for the long-term rate of return on plan assets before tax $ 1.0      
Other Assets [Member]        
Significant Accounting Policies [Line Items]        
Deferred costs 132.9 106.4    
Computer Software, Intangible Asset [Member]        
Significant Accounting Policies [Line Items]        
Amortization of software cost $ 30.6 $ 28.3 $ 26.2  
Computer Software, Intangible Asset [Member] | Minimum [Member]        
Significant Accounting Policies [Line Items]        
Finite-lived intangible asset, useful life 2 years      
Computer Software, Intangible Asset [Member] | Maximum [Member]        
Significant Accounting Policies [Line Items]        
Finite-lived intangible asset, useful life 7 years