Intangible Assets and Goodwill - Carrying Amount of Goodwill, by Segment (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2015 USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 47.5
Impairment charge	(7.0)
Foreign currency translation	(2.2)
Ending balance	38.3
Global Market Strategies
Goodwill [Roll Forward]
Beginning balance	28.0
Impairment charge	0.0
Foreign currency translation	0.0
Ending balance	28.0
Investment Solutions
Goodwill [Roll Forward]
Beginning balance	19.5
Impairment charge	(7.0)
Foreign currency translation	(2.2)
Ending balance	$ 10.3