Income Taxes - Reconciliation of Income Tax Computed At U. S. Federal Statutory Rate to Income Tax (Benefit) Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Tax at U.S. statutory rate	$ 1,506	$ 1,591	$ 1,456
State taxes, net of federal benefit	(1,374)	344	(13)
Noncontrolling interest	(455)	(260)	0
Non-deductible meals and entertainment	2,676	1,546	1,510
Foreign tax expense	175	(5)	(6)
Valuation allowances	(45,354)	(8,379)	(5,078)
Uncertain tax positions	1,145	1,090	917
Federal rate change	8,011	0	0
Other	(831)	(113)	420
Total income tax benefit	$ (34,501)	$ (4,186)	$ (794)