Acquisitions - Assets and Liabilities Acquired (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Sep. 01, 2021	Apr. 21, 2021	Dec. 31, 2020
Business Acquisition
Goodwill	$ 2,355,144			$ 838,428
VendEndgine
Business Acquisition
Identifiable intangible assets		$ 32,000
Goodwill		58,700
Deferred tax liabilities, net		$ (7,500)
NIC
Business Acquisition
Cash			$ 331,783
Accounts receivable			149,515
Other current assets			12,988
Other noncurrent assets			20,974
Identifiable intangible assets			790,000
Goodwill			1,438,603
Accounts payable			(150,099)
Accrued expenses			(63,809)
Other noncurrent liabilities			(11,493)
Deferred revenue			(3,294)
Deferred tax liabilities, net			(194,676)
Total consideration			$ 2,320,492