Equity and Share Based Payments - Redeemable Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands		9 Months Ended	12 Months Ended
	Jul. 16, 2018	Sep. 30, 2018	Dec. 31, 2017
Equity and Share Based Payments
Outstanding liquidation preference of Series B and Series C Preferred Stock			$ 51,800
Liquidation preference amount per share (in dollars per share)			$ 25.00
Series B 9.375% redeemable preferred stock
Equity and Share Based Payments
Outstanding liquidation preference of Series B and Series C Preferred Stock		$ 30,680	$ 30,680
Preferred stock, dividend rate (as a percent)		9.375%	9.375%
Series C 9.125% redeemable preferred stock
Equity and Share Based Payments
Outstanding liquidation preference of Series B and Series C Preferred Stock		$ 35,127	$ 35,127
Preferred stock, dividend rate (as a percent)		9.125%	9.125%
Curtis J. Timm
Equity and Share Based Payments
Preferred B stock approval percentage	67.00%
Curtis J. Timm | Series B 9.375% redeemable preferred stock
Equity and Share Based Payments
Liquidation preference amount per share (in dollars per share)	$ 46.09
Cumulative undeclared dividends in arrears	$ 14,000
Cumulative undeclared dividends in arrears (per share)	$ 21.09
Cumulative undeclared dividends in arrears, increase in every quarter (per share)	$ 0.5859
Amount of increase in cumulative undeclared dividends in arrears in each quarter	$ 390