Acquisitions of Businesses - Summary of the Valuation Methodologies Significant Assumptions, and Estimated Useful Lives of Acquired Intangible Assets (Details) - USD ($) $ in Thousands								12 Months Ended
	Oct. 18, 2021	Oct. 01, 2021	Apr. 20, 2021	Apr. 01, 2021	Dec. 01, 2020	Nov. 05, 2020	Oct. 05, 2020	Dec. 31, 2021	Dec. 31, 2020	Jun. 30, 2021
Inposia | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value				$ 14,269						$ 12,684
Inposia | Restatement Adjustment | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value				1,585
Davo Technologies LLC | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value								$ 4,651		6,427
Davo Technologies LLC | Restatement Adjustment | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value								(1,776)
Track1099 LLC | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value								5,850
CrowdReason LLC and CorrelationAdvisors | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value								$ 10,300
Transaction Tax Resources, Inc. | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value							$ 41,500		$ 49,000
Transaction Tax Resources, Inc. | Restatement Adjustment | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value							$ (7,500)
Business Licenses
Business Acquisition [Line Items]
Intangible assets Assigned value						$ 19,525			19,525
Impendulo | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value					$ 3,617				$ 3,617
Customer Relationships | Minimum
Business Acquisition [Line Items]
Estimated Useful Life								3 years	3 years
Customer Relationships | Maximum
Business Acquisition [Line Items]
Estimated Useful Life								10 years	10 years
Customer Relationships | Inposia
Business Acquisition [Line Items]
Intangible assets Assigned value				$ 3,288
Valuation Methodology				Multi-period excess earnings-income approach
Discount Rate				18.50%
Estimated Useful Life				8 years
Customer Relationships | Inposia | Previously Reported
Business Acquisition [Line Items]
Intangible assets Assigned value										1,585
Customer Relationships | Inposia | Restatement Adjustment
Business Acquisition [Line Items]
Intangible assets Assigned value				$ 1,703
Customer Relationships | Davo Technologies LLC
Business Acquisition [Line Items]
Intangible assets Assigned value			$ 2,050							4,350
Valuation Methodology			Multi-period excess earnings-income approach and replacement cost method-cost approach
Discount Rate			13.50%
Estimated Useful Life			6 years
Customer Relationships | Davo Technologies LLC | Restatement Adjustment
Business Acquisition [Line Items]
Intangible assets Assigned value			$ (2,300)
Customer Relationships | Track1099 LLC
Business Acquisition [Line Items]
Intangible assets Assigned value		$ 3,200
Valuation Methodology		Multi-period excess earnings-income approach
Discount Rate		28.00%
Estimated Useful Life		5 years
Customer Relationships | CrowdReason LLC and CorrelationAdvisors
Business Acquisition [Line Items]
Intangible assets Assigned value	$ 5,700
Valuation Methodology	Multi-period excess earnings-income approach
Discount Rate	18.00%
Customer Relationships | CrowdReason LLC and CorrelationAdvisors | Minimum
Business Acquisition [Line Items]
Estimated Useful Life	5 years
Customer Relationships | CrowdReason LLC and CorrelationAdvisors | Maximum
Business Acquisition [Line Items]
Estimated Useful Life	8 years
Customer Relationships | Transaction Tax Resources, Inc.
Business Acquisition [Line Items]
Valuation Methodology							Multi-period excess earnings-income approach
Discount Rate							18.00%
Estimated Useful Life							6 years
Customer Relationships | Transaction Tax Resources, Inc. | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value							$ 21,000
Customer Relationships | Transaction Tax Resources, Inc. | Previously Reported | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value									$ 26,000
Customer Relationships | Transaction Tax Resources, Inc. | Restatement Adjustment | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value							$ (5,000)
Customer Relationships | Business Licenses
Business Acquisition [Line Items]
Intangible assets Assigned value						$ 15,000
Valuation Methodology						Multi-period excess earnings-income approach
Discount Rate						19.50%
Estimated Useful Life						6 years
Customer Relationships | Impendulo
Business Acquisition [Line Items]
Valuation Methodology					Multi-period excess earnings-income approach
Discount Rate					20.00%
Estimated Useful Life					6 years
Customer Relationships | Impendulo | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value					$ 2,964
Developed Technology | Minimum
Business Acquisition [Line Items]
Estimated Useful Life								3 years	3 years
Developed Technology | Maximum
Business Acquisition [Line Items]
Estimated Useful Life								8 years	8 years
Developed Technology | Inposia
Business Acquisition [Line Items]
Intangible assets Assigned value				$ 9,572
Valuation Methodology				Relief from royalty-income approach
Discount Rate				18.50%
Estimated Useful Life				6 years
Developed Technology | Inposia | Previously Reported
Business Acquisition [Line Items]
Intangible assets Assigned value										9,572
Developed Technology | Davo Technologies LLC
Business Acquisition [Line Items]
Intangible assets Assigned value			$ 1,950							1,800
Valuation Methodology			Relief from royalty-income approach
Discount Rate			13.50%
Estimated Useful Life			5 years
Developed Technology | Davo Technologies LLC | Restatement Adjustment
Business Acquisition [Line Items]
Intangible assets Assigned value			$ 150
Developed Technology | Track1099 LLC
Business Acquisition [Line Items]
Intangible assets Assigned value		$ 1,250
Valuation Methodology		Relief from royalty-income approach
Discount Rate		28.00%
Estimated Useful Life		2 years
Developed Technology | CrowdReason LLC and CorrelationAdvisors
Business Acquisition [Line Items]
Intangible assets Assigned value	$ 3,900
Valuation Methodology	Relief from royalty-income approach
Discount Rate	18.00%
Estimated Useful Life	5 years
Developed Technology | Transaction Tax Resources, Inc.
Business Acquisition [Line Items]
Valuation Methodology							Relief from royalty-income approach and replacement cost method-cost approach
Developed Technology | Transaction Tax Resources, Inc. | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value							$ 9,600
Developed Technology | Transaction Tax Resources, Inc. | Minimum
Business Acquisition [Line Items]
Discount Rate							17.00%
Estimated Useful Life							3 years
Developed Technology | Transaction Tax Resources, Inc. | Maximum
Business Acquisition [Line Items]
Discount Rate							18.00%
Estimated Useful Life							6 years
Developed Technology | Transaction Tax Resources, Inc. | Previously Reported | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value									$ 9,600
Developed Technology | Business Licenses
Business Acquisition [Line Items]
Intangible assets Assigned value						$ 3,625
Valuation Methodology						Relief from royalty-income approach and replacement cost method-cost approach
Discount Rate						19.50%
Developed Technology | Business Licenses | Minimum
Business Acquisition [Line Items]
Estimated Useful Life						1 year
Developed Technology | Business Licenses | Maximum
Business Acquisition [Line Items]
Estimated Useful Life						5 years
Developed Technology | Impendulo
Business Acquisition [Line Items]
Valuation Methodology					Relief from royalty-income approach
Discount Rate					20.00%
Estimated Useful Life					6 years
Developed Technology | Impendulo | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value					$ 616
Noncompete Agreements | Minimum
Business Acquisition [Line Items]
Estimated Useful Life								3 years	3 years
Noncompete Agreements | Maximum
Business Acquisition [Line Items]
Estimated Useful Life								5 years	5 years
Noncompete Agreements | Inposia
Business Acquisition [Line Items]
Intangible assets Assigned value				$ 1,174
Valuation Methodology				With-and-without valuation-income approach
Discount Rate				21.00%
Estimated Useful Life				3 years
Noncompete Agreements | Inposia | Previously Reported
Business Acquisition [Line Items]
Intangible assets Assigned value										1,292
Noncompete Agreements | Inposia | Restatement Adjustment
Business Acquisition [Line Items]
Intangible assets Assigned value				$ (118)
Noncompete Agreements | Davo Technologies LLC
Business Acquisition [Line Items]
Intangible assets Assigned value			$ 564							191
Valuation Methodology			With-and-without valuation-income approach
Discount Rate			15.50%
Estimated Useful Life			5 years
Noncompete Agreements | Davo Technologies LLC | Restatement Adjustment
Business Acquisition [Line Items]
Intangible assets Assigned value			$ 373
Noncompete Agreements | Track1099 LLC
Business Acquisition [Line Items]
Intangible assets Assigned value		$ 1,300
Valuation Methodology		With-and-without valuation-income approach
Discount Rate		30.00%
Estimated Useful Life		5 years
Noncompete Agreements | CrowdReason LLC and CorrelationAdvisors
Business Acquisition [Line Items]
Intangible assets Assigned value	$ 100
Valuation Methodology	With-and-without valuation-income approach
Discount Rate	20.00%
Estimated Useful Life	5 years
Noncompete Agreements | Transaction Tax Resources, Inc.
Business Acquisition [Line Items]
Valuation Methodology							With-and-without valuation-income approach
Discount Rate							19.00%
Estimated Useful Life							5 years
Noncompete Agreements | Transaction Tax Resources, Inc. | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value							$ 1,800
Noncompete Agreements | Transaction Tax Resources, Inc. | Previously Reported | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value									$ 1,800
Noncompete Agreements | Business Licenses
Business Acquisition [Line Items]
Intangible assets Assigned value						$ 500
Valuation Methodology						With-and-without valuation-income approach
Discount Rate						19.50%
Estimated Useful Life						5 years
Tradename and Trademarks | Minimum
Business Acquisition [Line Items]
Estimated Useful Life								1 year	1 year
Tradename and Trademarks | Maximum
Business Acquisition [Line Items]
Estimated Useful Life								4 years	4 years
Tradename and Trademarks | Inposia
Business Acquisition [Line Items]
Intangible assets Assigned value				$ 235
Valuation Methodology				Relief from royalty-income approach
Discount Rate				18.50%
Estimated Useful Life				3 years
Tradename and Trademarks | Inposia | Previously Reported
Business Acquisition [Line Items]
Intangible assets Assigned value										235
Tradename and Trademarks | Davo Technologies LLC
Business Acquisition [Line Items]
Intangible assets Assigned value			$ 87							$ 86
Valuation Methodology			Relief from royalty-income approach
Discount Rate			13.50%
Estimated Useful Life			1 year
Tradename and Trademarks | Davo Technologies LLC | Restatement Adjustment
Business Acquisition [Line Items]
Intangible assets Assigned value			$ 1
Tradename and Trademarks | Track1099 LLC
Business Acquisition [Line Items]
Intangible assets Assigned value		$ 100
Valuation Methodology		Relief from royalty-income approach
Discount Rate		28.00%
Estimated Useful Life		2 years
Tradename and Trademarks | CrowdReason LLC and CorrelationAdvisors
Business Acquisition [Line Items]
Intangible assets Assigned value	$ 150
Valuation Methodology	Relief from royalty-income approach
Discount Rate	18.00%
Estimated Useful Life	2 years
Tradename and Trademarks | Transaction Tax Resources, Inc.
Business Acquisition [Line Items]
Valuation Methodology							Relief from royalty-income approach
Discount Rate							17.00%
Estimated Useful Life							2 years
Tradename and Trademarks | Transaction Tax Resources, Inc. | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value							$ 5,800
Tradename and Trademarks | Transaction Tax Resources, Inc. | Previously Reported | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value									$ 5,800
Tradename and Trademarks | Business Licenses
Business Acquisition [Line Items]
Intangible assets Assigned value						$ 400
Valuation Methodology						Relief from royalty-income approach
Discount Rate						19.50%
Estimated Useful Life						1 year
Tradename and Trademarks | Impendulo
Business Acquisition [Line Items]
Valuation Methodology					Relief from royalty-income approach
Discount Rate					20.00%
Estimated Useful Life					1 year
Tradename and Trademarks | Impendulo | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value					$ 37
Backlog
Business Acquisition [Line Items]
Estimated Useful Life								3 years	3 years
Backlog | CrowdReason LLC and CorrelationAdvisors
Business Acquisition [Line Items]
Intangible assets Assigned value	$ 450
Valuation Methodology	Multi-period excess earnings-income approach
Discount Rate	15.00%
Estimated Useful Life	1 year
Contract Backlog | Transaction Tax Resources, Inc.
Business Acquisition [Line Items]
Valuation Methodology							Multi-period excess earnings-income approach
Discount Rate							17.00%
Estimated Useful Life							3 years
Contract Backlog | Transaction Tax Resources, Inc. | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value							$ 3,300
Contract Backlog | Transaction Tax Resources, Inc. | Previously Reported | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value									$ 5,800
Contract Backlog | Transaction Tax Resources, Inc. | Restatement Adjustment | Fair Value
Business Acquisition [Line Items]
Intangible assets Assigned value							$ (2,500)