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)	(5,583)						(5,583)
Redeemable convertible series B preferred cash dividends	(200)						(200)
Equity-based compensation	102					102
Ending Balance at Mar. 31, 2018	87,911				$ 2	$ 141	$ 87,768
Ending Balance, Shares at Mar. 31, 2018			1,000,000		206,714,132
Preferred Stock Ending Balance ,Shares at Mar. 31, 2018				600,000
Preferred Stock Value, Ending Balance at Mar. 31, 2018	$ 503,713			$ 503,713

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