Business Acquisitions (Allocation of Aggregate Purchase Price) (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Jun. 04, 2021
Business Acquisition [Line Items]
Goodwill	$ 1,603,340	$ 1,531,455
Fiscal 2022 Acquisitions
Business Acquisition [Line Items]
Accounts receivable	6,703
Prepaid expenses and other current assets	897
Property and equipment	370
Goodwill	81,725
Other long-term assets	11
Accounts payable and accrued expenses	(3,383)
Deferred revenue	(19,274)
Deferred tax liability	(10,485)
Other long-term liabilities	(326)
Total	107,140
Fiscal 2022 Acquisitions | Trade names
Business Acquisition [Line Items]
Finite-lived intangible assets	11,902
Fiscal 2022 Acquisitions | Customer relationship
Business Acquisition [Line Items]
Finite-lived intangible assets	22,170
Fiscal 2022 Acquisitions | Other intangibles
Business Acquisition [Line Items]
Finite-lived intangible assets	$ 16,830
Fiscal 2021 Acquisitions
Business Acquisition [Line Items]
Accounts receivable			$ 3,278
Prepaid expenses and other current assets			2,512
Property and equipment			1,838
Operating lease right-of-use assets, noncurrent			5,888
Goodwill			55,439
Other long-term assets			62
Deferred tax asset			231
Accounts payable and accrued expenses			(2,656)
Other current liabilities			(14)
Deferred revenue		$ (9,500)	(7,048)
Operating lease liabilities, current			(7,191)
Deferred tax liability			(4,122)
Other long-term liabilities			(1,491)
Total			90,970
Fiscal 2021 Acquisitions | Trade names
Business Acquisition [Line Items]
Finite-lived intangible assets			10,007
Fiscal 2021 Acquisitions | Customer relationship
Business Acquisition [Line Items]
Finite-lived intangible assets			5,000
Fiscal 2021 Acquisitions | Other intangibles
Business Acquisition [Line Items]
Finite-lived intangible assets			$ 29,237
SEOmoz Acquisition
Business Acquisition [Line Items]
Accounts receivable				$ 3,278
Prepaid expenses and other current assets				2,512
Property and equipment				1,838
Operating lease right-of-use assets, noncurrent				5,888
Goodwill				41,192
Other long-term assets				62
Deferred tax asset				235
Accounts payable and accrued expenses				(2,656)
Other current liabilities				(14)
Deferred revenue				(7,048)
Operating lease liabilities, current				(7,191)
Deferred tax liability				(4,122)
Other long-term liabilities				(785)
Total				66,996
SEOmoz Acquisition | Trade names
Business Acquisition [Line Items]
Finite-lived intangible assets				7,200
SEOmoz Acquisition | Customer relationship
Business Acquisition [Line Items]
Finite-lived intangible assets				5,000
SEOmoz Acquisition | Other intangibles
Business Acquisition [Line Items]
Finite-lived intangible assets				$ 21,607