Revenue - Summary of Total Revenues (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation Of Revenue [Line Items]
Revenues	$ 204,530	$ 153,601
U.S.
Disaggregation Of Revenue [Line Items]
Revenues	190,476	142,672
Non-U.S.
Disaggregation Of Revenue [Line Items]
Revenues	14,054	10,929
Subscription and Returns, Tax Calculations | U.S.
Disaggregation Of Revenue [Line Items]
Revenues	100,500	76,396
Subscription and Returns, Tax Returns and Compliance Management | U.S.
Disaggregation Of Revenue [Line Items]
Revenues	73,727	52,847
Subscription and Returns, Interest Income on Funds Held for Customers | U.S.
Disaggregation Of Revenue [Line Items]
Revenues	208	141
Subscription and Returns
Disaggregation Of Revenue [Line Items]
Revenues	186,866	139,318
Subscription and Returns | U.S.
Disaggregation Of Revenue [Line Items]
Revenues	174,435	129,384
Professional Services
Disaggregation Of Revenue [Line Items]
Revenues	17,664	14,283
Professional Services | U.S.
Disaggregation Of Revenue [Line Items]
Revenues	$ 16,041	$ 13,288