Acquisitions - Additional Information (Details) $ in Millions	1 Months Ended			3 Months Ended	6 Months Ended
	May 31, 2018 USD ($)	Mar. 31, 2018 USD ($)	Oct. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) business	Dec. 31, 2018 USD ($) business	Dec. 31, 2017 USD ($)	Jun. 30, 2018 USD ($)	Feb. 28, 2018 USD ($)
Business Acquisition [Line Items]
Number of businesses acquired | business				0	0
Cash payments, net of cash acquired					$ 0.0	$ 30.2
Goodwill				$ 1,254.3	$ 1,254.3		$ 1,254.9
Summit
Business Acquisition [Line Items]
Aggregate purchase price			$ 30.6
Cash payments, net of cash acquired			26.4
Note payable acquired			1.4
Fair value of consideration liability			2.7
Potential maximum pay-out			11.0
Net tangible assets acquired			0.2
Goodwill			18.5
Intangible assets acquired			$ 12.0
ActivePath
Business Acquisition [Line Items]
Aggregate purchase price		$ 24.2
Cash payments, net of cash acquired		21.8
Note payable acquired		2.4
Goodwill		28.7
Intangible assets acquired		5.6
Net tangible liabilities acquired		$ 10.0
FundAssist
Business Acquisition [Line Items]
Aggregate purchase price	$ 47.7
Cash payments, net of cash acquired	41.3
Fair value of consideration liability	6.4
Goodwill	29.2
Intangible assets acquired	20.4
Net tangible liabilities acquired	$ 1.9
Inveshare
Business Acquisition [Line Items]
Deferred payment								$ 40.0
Software Technology
Business Acquisition [Line Items]
Useful life of intangible assets acquired	5 years
Software Technology | Summit
Business Acquisition [Line Items]
Useful life of intangible assets acquired			5 years
Software Technology | ActivePath
Business Acquisition [Line Items]
Useful life of intangible assets acquired		5 years
Customer Relationships | Summit
Business Acquisition [Line Items]
Useful life of intangible assets acquired			7 years
Customer Relationships | ActivePath
Business Acquisition [Line Items]
Useful life of intangible assets acquired		2 years
Customer Relationships | FundAssist
Business Acquisition [Line Items]
Useful life of intangible assets acquired	6 years