Acquisitions - Narrative (Details) - USD ($) $ in Millions			3 Months Ended		12 Months Ended
		Jun. 13, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Business Acquisition [Line Items]
Noncash or part noncash acquisition, value of assets acquired			$ 4.1	$ 0.9
Payments to acquire businesses, net of cash acquired			(4.1)	$ (0.9)
Finite-lived intangible assets acquired			68.0
Goodwill acquired during period	[1]				$ 34.3
Acquired deferred tax liabilities			17.0
Acquired other assets and liabilities			9.1
Other
Business Acquisition [Line Items]
Goodwill acquired during period	[1]		$ 34.3		$ 34.3
Noncontrolling Interest
Business Acquisition [Line Items]
Equity interest of a subsidiary issued for an acquisition (value)		$ 44.4
Equity interest issued for an acquisition (in shares)		1,953,407	1,953,407
Acquired businesses
Business Acquisition [Line Items]
Noncash or part noncash acquisition, value of assets acquired		$ 94.4
Payments to acquire businesses, net of cash acquired		$ (50.0)

[1] Non-tax deductible addition associated with the Transaction (as defined below, see Note 8. Equity and Note 11. Acquisitions to the Consolidated Financial Statements).