Segment Information - Summary of Operations by Segment (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Revenue	$ 515.4	$ 554.5
Operating income (loss)	20.1	25.2
Services
Segment Reporting Information [Line Items]
Revenue	425.9	474.0
Operating income (loss)	(14.0)	(1.4)
Technology
Segment Reporting Information [Line Items]
Revenue	89.5	80.5
Operating income (loss)	42.2	28.3
Intersegment
Segment Reporting Information [Line Items]
Revenue	(2.5)	(2.4)
Intersegment | Services
Segment Reporting Information [Line Items]
Revenue	0.0	0.0
Intersegment | Technology
Segment Reporting Information [Line Items]
Revenue	2.5	2.4
Operating Segments
Segment Reporting Information [Line Items]
Operating income (loss)	28.2	26.9
Operating Segments | Services
Segment Reporting Information [Line Items]
Revenue	425.9	474.0
Operating Segments | Technology
Segment Reporting Information [Line Items]
Revenue	92.0	82.9
Corporate
Segment Reporting Information [Line Items]
Revenue	(2.5)	(2.4)
Operating income (loss)	$ (8.1)	$ (1.7)