Segment Information - Additional Information (Detail)		3 Months Ended			6 Months Ended
	Jan. 01, 2018 USD ($)	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Jun. 30, 2019 USD ($) segment	Jun. 30, 2018 USD ($)
Segment Reporting Information [Line Items]
Revenue		$ 753,800,000	$ 667,400,000		$ 1,449,600,000	$ 1,375,800,000
Number of business segments | segment					2
Profit included in operating income		87,000,000	54,000,000		$ 129,900,000	155,800,000
Technology
Segment Reporting Information [Line Items]
Revenue		100,400,000	80,700,000		184,100,000	220,600,000
Profit included in operating income		55,100,000	38,200,000		84,500,000	120,200,000
Technology | Software License Extensions and Renewals
Segment Reporting Information [Line Items]
Revenue	$ 53,000,000			$ 53,000,000
Technology | Other Technology | Segment Reconciling Items
Segment Reporting Information [Line Items]
Profit included in operating income		$ 0	$ 2,200,000		$ 200,000	$ 2,200,000