Restructuring Costs - Schedule of Restructuring Costs Incurred by Reportable Business Segment (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 7.9	$ 13.3
Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	2.7	0.6
Live [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	0.8	1.1
Learn [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	1.8	4.0
Work [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	1.1	2.8
Play [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	1.0	2.7
Other [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 0.5	$ 2.1