Restructuring Costs - Schedule of Restructuring Costs Incurred by Reportable Business Segment (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 38.4	$ 13.0	$ 82.2	$ 41.7
Corporate [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	27.8	1.1	40.1	17.3
Live [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	3.0	2.9	10.7	2.3
Learn [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	3.0	3.7	8.8	8.8
Work [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	1.6	1.7	7.0	4.3
Play [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	1.6	2.3	10.6	2.6
Other [Member] | Operating Segments [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring costs	$ 1.4	$ 1.3	$ 5.0	$ 6.4