Corporate Investments and Funds Held For Clients - Cash and Cash Equivalents and Investments (Details) - USD ($) $ in Thousands		Sep. 30, 2022	Dec. 31, 2021	Sep. 30, 2021
Corporate Investments and Funds Held for Clients [Line Items]
Cash and cash equivalents, amortized cost		$ 317,163	$ 277,978
Funds held for clients cash and cash equivalents, amortized cost		1,501,276	1,534,894
Amortized cost		252,720
Total investments, amortized cost		2,071,159	2,124,551
Gross unrealized losses	[1]	(4,881)
Cash and cash equivalents, fair value		317,163	277,978	$ 230,926
Funds held for clients cash and cash equivalents, fair value		1,501,276	1,534,894
Fair value		247,839
Total investments, fair value		2,066,278	2,124,551
Available-for-sale Securities [Member] | Commercial Paper [Member]
Corporate Investments and Funds Held for Clients [Line Items]
Amortized cost	[2]	53,478	311,679
Gross unrealized losses	[1],[2]	(140)
Fair value	[2]	53,338	$ 311,679
Available-for-sale Securities [Member] | U.S. Treasury Securities [Member]
Corporate Investments and Funds Held for Clients [Line Items]
Amortized cost	[2]	174,242
Gross unrealized losses	[1],[2]	(4,741)
Fair value	[2]	169,501
Available-for-sale Securities [Member] | Certificates of Deposit [Member]
Corporate Investments and Funds Held for Clients [Line Items]
Amortized cost	[2]	25,000
Fair value	[2]	$ 25,000

[1] These securities have been in an unrealized loss position for a period of less than 12 months.

[2] All available-for-sale securities were included within funds held for clients.