Unaudited Condensed Consolidated Statement of Changes in Stockholders' Equity - 9 months ended Sep. 30, 2018 - USD ($) $ in Thousands	Total	Class A Voting Common Stock	Series A-1 Preferred Stock	Class B Non-Voting Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Class B Non-Voting Common Stock	Accumulated Deficit
Beginning balance (in shares) at Dec. 31, 2017		24,506,647	83,968
Beginning balance at Dec. 31, 2017	$ 203,690	$ 142,655			$ 174,871		$ (113,836)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Payment-in-kind dividends (in shares)			5,796
Issued pursuant to stock based compensation plan (in shares)		130,480
Issued pursuant to stock-based compensation plan	(601)				(601)
Retirement of Class B Common Stock				$ (10)		$ (10)
Stock-based compensation	199				199
Net loss	(57,840)						(57,840)
Ending balance at Sep. 30, 2018	$ 145,438	$ 142,655			$ 174,459		$ (171,676)
Ending balance (in shares) at Sep. 30, 2018		24,637,127	89,764