XML 54 R43.htm IDEA: XBRL DOCUMENT v3.21.2
Unearned Revenues (Details) - USD ($)
$ in Millions
9 Months Ended 12 Months Ended
Sep. 30, 2021
Dec. 31, 2020
Deferred Revenue Disclosure [Abstract]    
Decrease in deferred revenue $ 39.7  
Deferred revenue, revenue recognized   $ 45.4