Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies - Additional Information (Detail)

v3.20.1
Summary of Significant Accounting Policies - Additional Information (Detail)
$ in Millions
 3 Months Ended 12 Months Ended
Sep. 30, 2019
USD ($)
Mar. 31, 2020
USD ($)
director
shares
Mar. 31, 2019
USD ($)
shares
Mar. 31, 2018
USD ($)
shares
Apr. 01, 2019
USD ($)
Apr. 01, 2018
USD ($)
Summary Of Significant Accounting Policies [Line Items]            
Intangible assets, net   $ 166.7 $ 174.4      
Goodwill   $ 196.9 201.1 $ 4.9    
Ownership interest rate percentage (as percent)   100.00%        
Cumulative effect of new accounting principle in period of adoption         $ 0.2 $ 1,160.3
Equity awards vested percentage after first year   25.00%        
Equity awards vested percentage after second year   25.00%        
Equity awards vested percentage after third year   50.00%        
Reported free cash flow percentage   35.00%        
Operating lease right-of-use-assets   $ 40.5 0.0      
Operating lease liability   $ 55.7        
Understatement of Cash Flows from Operating Activities            
Summary Of Significant Accounting Policies [Line Items]            
Payments to AICF $ 8.0          
Reported Free Cash Flow            
Summary Of Significant Accounting Policies [Line Items]            
Payments to AICF $ 100.9          
Understatement of Net Cash Used in Investing and Operating Activities            
Summary Of Significant Accounting Policies [Line Items]            
Amount of error     $ 16.4 $ 6.5    
Accounting Standards Update 2016-02            
Summary Of Significant Accounting Policies [Line Items]            
Cumulative effect of new accounting principle in period of adoption         0.2  
Operating lease right-of-use-assets         79.7  
Operating lease liability         $ 82.0  
Restricted Stock Units (RSUs) [Member]            
Summary Of Significant Accounting Policies [Line Items]            
Potential diluted common shares outstanding | shares   0 0 0    
Contingent Shares Not Expected To Vest [Member]            
Summary Of Significant Accounting Policies [Line Items]            
Potential diluted common shares outstanding | shares   1,500,000 2,200,000 1,600,000    
AICF Funding            
Summary Of Significant Accounting Policies [Line Items]            
Ownership interest rate percentage (as percent)   0.00%        
AICF Funding            
Summary Of Significant Accounting Policies [Line Items]            
Number of directors appointed by Company | director   3        
AICF Funding | New South Wales, Australia [Member]            
Summary Of Significant Accounting Policies [Line Items]            
Number of directors appointed by NSW government | director   2        
Minimum            
Summary Of Significant Accounting Policies [Line Items]            
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life   2 years        
Maximum            
Summary Of Significant Accounting Policies [Line Items]            
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life   13 years