Description of the Business and Summary of Significant Accounting Policies - Aggregate Business Acquisitions Completed (Details) CAD / shares in Units, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017 CAD CAD / shares	Sep. 30, 2017 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($)	Dec. 31, 2016 USD ($)
Business Acquisition [Line Items]
Cash paid, net of cash acquired			$ 57.7	$ 0.0
Excess purchase price allocated to Goodwill					$ 2,961.3	$ 2,888.4
Earnings Based Metrics
Business Acquisition [Line Items]
Maximum contingent consideration					38.5
Minimum
Business Acquisition [Line Items]
Intangible assets acquired, discount rate			9.00%
Intangible assets acquired, royalty rate			1.00%
Maximum
Business Acquisition [Line Items]
Intangible assets acquired, discount rate			20.00%
Intangible assets acquired, royalty rate			16.00%
Aggregate total
Business Acquisition [Line Items]
Total Consideration			$ 66.0
Cash paid, net of cash acquired			$ 57.7
Contingent consideration					7.5
Allocation of purchase price to Intangible assets, net					56.4
Weighted average useful life of acquired intangible assets			8 years 3 months
Excess purchase price allocated to Goodwill					$ 14.6
NYX
Business Acquisition [Line Items]
Total Consideration	CAD 775,000,000	$ 631.0
Aggregate purchase price (in CAD per share) | CAD / shares	CAD 2.40
Contingent termination fee | CAD	CAD 30,000,000