Intangible Assets and Goodwill - Carrying Amount of Goodwill, by Segment (Details) $ in Millions	9 Months Ended
	Sep. 30, 2015 USD ($)
Goodwill [Roll Forward]
Balance at beginning of period	$ 47.5
Foreign currency translation	(1.8)
Balance at end of period	45.7
Operating Segments | Global Market Strategies
Goodwill [Roll Forward]
Balance at beginning of period	28.0
Foreign currency translation	0.0
Balance at end of period	28.0
Operating Segments | Investment Solutions
Goodwill [Roll Forward]
Balance at beginning of period	19.5
Foreign currency translation	(1.8)
Balance at end of period	$ 17.7