Series C Convertible Preferred Stock (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Mar. 01, 2016 USD ($) director $ / shares shares	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares
Class of Stock [Line Items]
Dividend accrual, percentage	1.25%
Dividends, Preferred Stock		$ 0.0	$ 0.0
Temporary Equity, Liquidation Preference Per Share | $ / shares	$ 1,000
Optional conversion price for holders (in dollars per share) | $ / shares	$ 5.00
Conversion Of Stock, Percentage Of Number Of Shares Of Common Stock Outstanding	19.99%
Temporary Equity, Conversion, Common Stock Equivalent | shares		87,051,524.000000	87,100,000.0
Conversion Of Stock, Stock Price Trigger | $ / shares	$ 10.00
Preferred Stock, Change Of Control Event, Repurchase Price, Percentage Of Liquidation Preference	100.00%
Minimum [Member]
Class of Stock [Line Items]
Dividend accrual, percentage	1.25%
Maximum [Member]
Class of Stock [Line Items]
Dividend accrual, percentage	5.00%
Preferred Stock, Voting Rights, Election Of Directors, Number Of Directors | director	3
Private Placement [Member]
Class of Stock [Line Items]
Preferred Stock, Discount on Shares	$ 8.7
Series C Preferred Stock [Member]
Class of Stock [Line Items]
Temporary Equity, Shares Issued | shares	435,000
Temporary Equity, Stock Issued During Period, Value, New Issues	$ 435.0
Dividends Accrued		$ 41.5