Accounting for Series A Preferred Stock (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Mar. 31, 2016	Jun. 30, 2017	Jun. 30, 2016
Class Of Stock [Line Items]
Proceeds from issuance of preferred stock and warrants	$ 994.1		$ 994.1
Transaction fees			(24.8)
Net Proceeds- Initial Relative Fair Value Allocation			969.3
Allocation to BCF		$ 0.0	614.4
Per balance sheet upon issuance			614.4
Series A Warrants [Member]
Class Of Stock [Line Items]
Net Proceeds- Initial Relative Fair Value Allocation			135.7
Per balance sheet upon issuance			135.7
Series B Warrants [Member]
Class Of Stock [Line Items]
Net Proceeds- Initial Relative Fair Value Allocation			46.5
Per balance sheet upon issuance			46.5
Series A Preferred Stock [Member]
Class Of Stock [Line Items]
Net Proceeds- Initial Relative Fair Value Allocation			787.1
Allocation to BCF			(614.4)
Per balance sheet upon issuance			$ 172.7