Condensed Consolidated Statements of Changes in Redeemable Convertible Preferred Stock and Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total		Convertible Series A Preferred Stock [Member]	Series B Redeemable Convertible Preferred Stock [Member]	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained earnings [Member]
Beginning Balance at Dec. 31, 2016	$ 194,136				$ 2	$ 108,415	$ 85,719
Beginning Balance, Shares at Dec. 31, 2016			1,000,000		206,380,800
Preferred Stock Beginning Balance, Shares at Dec. 31, 2016				600,000
Preferred Stock Value, Beginning Balance at Dec. 31, 2016				$ 502,213
Net income (loss)	25,882						25,882
Redeemable convertible series B preferred cash dividends	(18,050)						(18,050)
Reduction of accrued fees incurred relating to Series B preferred stock issuance				$ 1,500
Reclassification of derivative asset	(108,893)					(108,893)
Issuance of common stock under restricted stock compensation arrangement, Shares					333,332
Equity-based compensation	517					517
Ending Balance at Dec. 31, 2017	93,592	[1]			$ 2	39	93,551
Ending Balance, Shares at Dec. 31, 2017			1,000,000		206,714,132
Preferred Stock Ending Balance ,Shares at Dec. 31, 2017				600,000
Preferred Stock Value, Ending Balance at Dec. 31, 2017	503,713	[1]		$ 503,713
Net income (loss)	(7,579)						(7,579)
Redeemable convertible series B preferred cash dividends	(200)						(200)
Issuance of common stock under restricted stock compensation arrangement, Shares					298,508
Issuance of common stock as payment of Series B preferred stock dividends						12,933	(12,933)
Issuance of common stock as payment of Series B preferred stock dividends, Shares					9,652,268
Equity-based compensation	178					178
Ending Balance at Jun. 30, 2018	85,991				$ 2	$ 13,150	$ 72,839
Ending Balance, Shares at Jun. 30, 2018			1,000,000		216,664,908
Preferred Stock Ending Balance ,Shares at Jun. 30, 2018				600,000
Preferred Stock Value, Ending Balance at Jun. 30, 2018	$ 503,713			$ 503,713

[1] Balances derived from audited financial statements as of December 31, 2017.