Restructuring Costs - Schedule of Restructuring Costs Incurred by Reportable Business Segment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 111.9	$ 74.9	$ 77.2
Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	55.8	20.9	53.4
Live [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	14.0	18.8	3.6
Learn [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	10.1	14.0	9.3
Work [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	11.6	6.4	7.7
Play [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	14.3	6.7	0.3
Other [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 6.1	$ 8.1	$ 2.9