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Acquisitions - Additional Information (Details)			3 Months Ended	12 Months Ended
Acquisitions - Additional Information (Details)	Feb. 01, 2021 USD ($)	Nov. 17, 2020 USD ($)	Dec. 31, 2021 USD ($) business	Sep. 30, 2021 USD ($) business
Finite-Lived Intangible Assets [Line Items]
Number of businesses acquired \| business				8
2021 Business Combinations
Finite-Lived Intangible Assets [Line Items]
Number of businesses acquired \| business			2
Total purchase consideration			$ 100,481,000
Proceeds from issuance of long-term debt used to fund the acquisition			95,000,000
Contingent consideration			$ 5,481,000
Estimated amortization period			14 years
Acquisition-related costs			$ 228,000
Potential additional consideration			$ 18,000,000
2021 Business Combinations \| Trade name
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period			5 years
2021 Business Combinations \| Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period			5 years
2021 Business Combinations \| Capitalized software
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period			7 years
2021 Business Combinations \| Minimum \| Acquired merchant relationships
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period			9 years
2021 Business Combinations \| Maximum \| Acquired merchant relationships
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period			19 years
BIS
Finite-Lived Intangible Assets [Line Items]
Total purchase consideration	$ 95,495,000
Proceeds from issuance of long-term debt used to fund the acquisition	$ 52,500,000
Estimated amortization period	19 years
Acquisition-related costs	$ 374,000
Potential additional consideration	16,000,000
Contingent consideration	7,750,000
BIS \| Class A Common Stock
Finite-Lived Intangible Assets [Line Items]
Common units issued to seller	$ 35,245,000
BIS \| Acquired merchant relationships
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period	19 years
BIS \| Trade name
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period	5 years
BIS \| Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period	3 years
BIS \| Capitalized software
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period	10 years
ImageSoft Inc
Finite-Lived Intangible Assets [Line Items]
Total purchase consideration		$ 46,300,000
Proceeds from issuance of long-term debt used to fund the acquisition		40,000,000
Contingent consideration		$ 6,300,000
Estimated amortization period		19 years
Acquisition-related costs		$ 403,000
Potential additional consideration		$ 20,000,000
ImageSoft Inc \| Acquired merchant relationships
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period		20 years
ImageSoft Inc \| Trade name
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period	5 years
ImageSoft Inc \| Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period	3 years
ImageSoft Inc \| Capitalized software
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period		7 years
Other Business Combinations
Finite-Lived Intangible Assets [Line Items]
Number of businesses acquired \| business			6
Total purchase consideration				$ 65,527,000
Proceeds from issuance of long-term debt used to fund the acquisition				$ 57,000,000
Estimated amortization period				16 years
Acquisition-related costs				$ 1,101,000
Potential additional consideration				50,200,000
Contingent consideration				$ 8,527,000
Other Business Combinations \| Trade name
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period				4 years
Other Business Combinations \| Non-compete agreements
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period				4 years
Other Business Combinations \| Capitalized software
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period				7 years
Other Business Combinations \| Minimum \| Acquired merchant relationships
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period				10 years
Other Business Combinations \| Maximum \| Acquired merchant relationships
Finite-Lived Intangible Assets [Line Items]
Estimated amortization period				25 years
Other Business Combinations \| Proprietary Software and Payments
Finite-Lived Intangible Assets [Line Items]
Number of businesses acquired \| business			5
Other Business Combinations \| Merchant Services Segment
Finite-Lived Intangible Assets [Line Items]
Number of businesses acquired \| business			1