Segment Information - Summary of Operations by Segment (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Revenue	$ 438.8	$ 569.4	$ 954.2	$ 1,123.9
Operating income (loss)	(8.5)	53.0	11.6	78.2
Services
Segment Reporting Information [Line Items]
Revenue	396.0	481.0	821.9	955.0
Operating income (loss)	(1.6)	9.0	(15.6)	7.6
Technology
Segment Reporting Information [Line Items]
Revenue	42.8	88.4	132.3	168.9
Operating income (loss)	1.0	51.3	43.2	79.6
Intersegment
Segment Reporting Information [Line Items]
Revenue	(2.4)	(2.1)	(4.9)	(4.5)
Intersegment | Services
Segment Reporting Information [Line Items]
Revenue	0.0	0.0	0.0	0.0
Intersegment | Technology
Segment Reporting Information [Line Items]
Revenue	2.4	2.1	4.9	4.5
Operating Segments
Segment Reporting Information [Line Items]
Operating income (loss)	(0.6)	60.3	27.6	87.2
Operating Segments | Services
Segment Reporting Information [Line Items]
Revenue	396.0	481.0	821.9	955.0
Operating Segments | Technology
Segment Reporting Information [Line Items]
Revenue	45.2	90.5	137.2	173.4
Corporate
Segment Reporting Information [Line Items]
Revenue	(2.4)	(2.1)	(4.9)	(4.5)
Operating income (loss)	$ (7.9)	$ (7.3)	$ (16.0)	$ (9.0)