Significant Business Acquistitions (Details) - USD ($) $ in Millions			3 Months Ended	6 Months Ended
		Feb. 24, 2016	Jun. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill			$ 517.9	$ 517.9	$ 458.3
Kaufman Rossin Fund Services LLC
Business Acquisition [Line Items]
Cash paid		$ 94.7
Working capital adjustment			0.3	0.3
Goodwill, Expected Tax Deductible Amount		61.0
Cash and cash equivalents		1.0
Accounts receivable		2.9
Other current assets		0.1
Investments		0.5
Properties	[1]	6.8
Intangible assets		23.4
Goodwill		61.0
Total assets		95.7
Deferred revenue		0.6
Other current liabilities		0.4
Total liabilities		1.0
Net assets acquired		94.7
Total revenues			6.4	8.7
Net pretax income			$ 1.5	$ 2.0
Acquired software | Kaufman Rossin Fund Services LLC
Business Acquisition [Line Items]
Properties		$ 6.5

[1] Includes $6.5 million of acquired software with a weighted-average useful life of 6 years.