Quarterly report pursuant to Section 13 or 15(d)

Significant Accounting Policies - Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash for Balance Sheets and Cash Flows (Detail)

v3.21.1
Significant Accounting Policies - Summary of Reconciliation of Cash, Cash Equivalents and Restricted Cash for Balance Sheets and Cash Flows (Detail) - USD ($)
$ in Millions
Mar. 31, 2021
Dec. 31, 2020
Mar. 31, 2020
Dec. 31, 2019
Cash, Cash Equivalents and Restricted Cash [Line Items]        
Cash and cash equivalents $ 611.7 $ 1,045.4    
Total cash, cash equivalents, and restricted cash shown in the statement of cash flows 620.3 1,054.0 $ 952.1 $ 847.5
Prepaid expenses and other current assets [Member]        
Cash, Cash Equivalents and Restricted Cash [Line Items]        
Restricted cash 2.5 2.5    
Other Assets [Member]        
Cash, Cash Equivalents and Restricted Cash [Line Items]        
Restricted cash $ 6.1 $ 6.1