Equity Method Investments - Schedule of Equity Investments in Affiliates (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Equity method investments	$ 181.9	$ 185.0
Mars
Schedule of Equity Method Investments [Line Items]
Equity method investments	85.0	84.0
Amount equity investment exceeds equity in net assets	11.3	11.1
Bengal
Schedule of Equity Method Investments [Line Items]
Equity method investments	74.7	75.6
Gain from contribution on equity investments	6.1	6.0
Poseidon
Schedule of Equity Method Investments [Line Items]
Equity method investments	22.2	25.4
Amount equity investment exceeds equity in net assets	$ 10.5	$ 10.3