Income Taxes (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax liabilities:
Property and equipment	$ 4,333	$ 6,858
Intangible assets	17,640	24,987
Prepaid expenses	317	619
Total deferred tax liabilities	22,290	32,464
Deferred tax assets:
Allowance for doubtful accounts	116	224
Compensation	1,058	2,421
Other accrued liabilities	44	78
Deferred Tax Assets, Gross, Total	1,218	2,723
Less: valuation allowance	0	0
Total net deferred tax assets	1,218	2,723
Net deferred tax liabilities	21,072	29,741
Current portion of deferred tax assets	300	1,022
Non-current portion of deferred tax liabilities	(21,072)	(29,741)
Net deferred tax liabilities	$ (21,072)	$ (29,741)