Accounting Policies - Summary of Cash and Cash Equivalents (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Cash accounts, Amount	$ 580,047	$ 571,587
Money market funds, Amount	87,620	341,085
Total	$ 667,667	$ 912,672
Cash
Percent Of Cash And Cash Equivalents	86.90%	62.60%
Money Market Funds
Percent Of Cash And Cash Equivalents	13.10%	37.40%