Fair Value Of Assets And Liabilities (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Sep. 30, 2017	Dec. 31, 2016	Dec. 16, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Discount Rate			2.70%
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value			$ 62.2	$ 95.7
Contingent consideration paid	$ (34.2)	$ (281.6)	(34.2)
Long-term debt (net of current maturities and loan origination fees of $0.5 at both September 30, 2017 and December 31, 2016)			510.7	312.8
Debt Instrument, Interest Rate, Stated Percentage					5.375%
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Gain (Loss) Included in Earnings			0.7
Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash equivalents and restricted cash			36.0	34.1
Deferred Payment-Founder, Fair Value			0.0	0.0
Business Combination, Contingent Consideration, Liability			0.0	0.0
Assets, Fair Value Disclosure			36.0	34.1
Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value			0.0	622.5
Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value			62.2	95.7
Increase (Decrease) in Deferred Founder Payment Liability			0.0
Deferred Payment-Founder, Change in Fair Value			0.5
Business Combination, Contingent Consideration Arrangements, Change in Amount of Contingent Consideration, Liability			0.2
Cash equivalents and restricted cash			0.0	0.0
Deferred Payment-Founder, Fair Value			28.3	27.8
Business Combination, Contingent Consideration, Liability			$ 33.9	67.9
Unsecured Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt (net of current maturities and loan origination fees of $0.5 at both September 30, 2017 and December 31, 2016)				$ 600.0