Schedule I - Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 70,726	$ 19,242
Prepaid expenses	3,566	2,675
Total current assets	150,743	82,708
Deferred tax assets	2,544	1,115
Total assets	731,342	697,242
Liabilities and Stockholders’ Equity
Total current liabilities	47,439	43,720
Long-term debt	521,924	644,158
Other long-term liabilities	24,732	36,283
Total liabilities	595,538	725,177
Common stock	353	149
Additional paid-in capital	361,628	177,276
Retained earnings	(222,403)	(201,557)
Accumulated other comprehensive (loss) income	(3,774)	(3,803)
Stockholders' Equity Attributable to Parent	135,804	(27,935)	$ 16,428	$ 100,537
Total liabilities and stockholders' equity	731,342	697,242
Parent Company [Member]
Current assets
Cash and cash equivalents	13,549	2,201	$ 10,171	$ 25,972
Prepaid expenses	49	54
Total current assets	13,598	2,255
Deferred tax assets	0	0
Investments in subsidiaries	122,972	121,118
Total assets	136,570	123,373
Liabilities and Stockholders’ Equity
Accounts Payable and Accrued Liabilities, Current	0	0
Intercompany payables	766	399
Total current liabilities	766	399
Long-term debt	0	149,588
Other long-term liabilities	0	1,321
Total liabilities	766	151,308
Common stock	353	149
Additional paid-in capital	361,628	177,276
Retained earnings	(222,403)	(201,557)
Accumulated other comprehensive (loss) income	(3,774)	(3,803)
Stockholders' Equity Attributable to Parent	135,804	(27,935)
Total liabilities and stockholders' equity	$ 136,570	$ 123,373