Significant Accounting Policies (Narrative) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Apr. 15, 2019	Dec. 31, 2014
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			6 years 3 months 10 days	6 years 1 month 2 days
Amortization of capitalized contract costs			$ 76,600,000	$ 57,500,000	$ 44,800,000
Short-term contract acquisition cost	$ 82,400,000	$ 71,500,000	82,400,000	71,500,000
Long-term contract acquisition cost	144,200,000	124,700,000	144,200,000	124,700,000
Retirement of property and equipment			196,700,000	9,300,000
Goodwill and intangible asset impairment	0	0
Non-cash impairment charges			19,400,000
Finite-Lived Intangible Assets, Net	760,293,000		760,293,000
Amount capitalized related to internal use software			3,700,000	2,100,000
Amount expensed related to internal use software			5,800,000	12,600,000	19,700,000
Capitalized costs for internally developed software to be sold as a service	31,100,000	22,300,000	31,100,000	22,300,000
Amount expensed related to internally developed computer software to be sold as a service			12,600,000	11,800,000	13,000,000
Write off capitalized internal use software			6,200,000
Advertising costs			135,500,000	118,400,000	90,400,000
Senior Notes Due 2019
Significant Accounting Policies [Line Items]
Stated interest rate (percent)						0.50%	0.50%
Pension Plan | Foreign Plan
Significant Accounting Policies [Line Items]
Termination indemnities	$ 10,000,000	$ 14,000,000	10,000,000	14,000,000
Termination indemnities, compensation expense			$ 1,200,000	$ 1,200,000	1,600,000
Computer equipment
Significant Accounting Policies [Line Items]
Estimated useful lives of property and equipment			3 years
Equipment and furniture
Significant Accounting Policies [Line Items]
Estimated useful lives of property and equipment			7 years
Enterprise Resource Planning Systems
Significant Accounting Policies [Line Items]
Estimated useful lives of property and equipment			7 years
Buildings
Significant Accounting Policies [Line Items]
Estimated useful lives of property and equipment			40 years
Minimum
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			2 years
Maximum
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			7 years
Maximum | Leasehold improvements
Significant Accounting Policies [Line Items]
Estimated useful lives of property and equipment			10 years
Contract-based intangible assets | Minimum
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			3 years
Contract-based intangible assets | Maximum
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			5 years
Patents | Minimum
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			7 years
Patents | Maximum
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			10 years
Product related intangible assets
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			6 years 1 month 2 days	6 years 21 days
Product related intangible assets | Cost of net revenues
Significant Accounting Policies [Line Items]
Amortization and impairment of intangible assets			$ 91,400,000	$ 32,800,000
Other
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			6 years 6 months 25 days	6 years 2 months 19 days
Other | Operating expenses
Significant Accounting Policies [Line Items]
Amortization and impairment of intangible assets			$ 66,300,000	$ 2,800,000
Internal use software | Minimum
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			3 years
Internal use software | Maximum
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			7 years
Internally developed software to be sold as a service | Minimum
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			2 years
Internally developed software to be sold as a service | Maximum
Significant Accounting Policies [Line Items]
Estimated useful lives of intangible assets			5 years
Primarily Cedexis Developed Technology
Significant Accounting Policies [Line Items]
Non-cash impairment charges					13,200,000
Finite-Lived Intangible Assets, Net					$ 4,100,000