Goodwill and Acquired Client Relationships (Tables)

12 Months Ended

Dec. 31, 2017

Goodwill and Intangible Assets Disclosure [Abstract]

Schedule of Changes in Goodwill

The following tables present the changes in the Company’s consolidated Affiliates’ Goodwill and components of Acquired client relationships (net):

	Goodwill
	2016			2017
Balance, as of January 1,	$	2,668.4		$	2,628.1
Foreign currency translation	(40.3		)	34.4
Balance, as of December 31,	$	2,628.1		$	2,662.5

Schedule of Changes in, and the Components of, Acquired Client Relationships

	Acquired Client Relationships (Net)
	Definite-lived									Indefinite-lived			Total
	Gross Book Value			Accumulated Amortization			Net Book Value			Net Book Value			Net Book Value
Balance, as of December 31, 2015	$	1,301.8		$	(680.4	)	$	621.4		$	1,065.0		$	1,686.4
Intangible amortization and impairments	—			(107.7		)	(107.7		)	(2.5		)	(110.2		)
Foreign currency translation	(11.8		)	—			(11.8		)	(67.0		)	(78.8		)
Balance, as of December 31, 2016	$	1,290.0		$	(788.1	)	$	501.9		$	995.5		$	1,497.4
Intangible amortization and impairments	—			(86.4		)	(86.4		)	—			(86.4		)
Foreign currency translation	5.5			—			5.5			33.2			38.7
Balance, as of December 31, 2017	$	1,295.5		$	(874.5	)	$	421.0		$	1,028.7		$	1,449.7