Income Taxes - Carrying amounts of assets and liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deferred tax liabilities
Accelerated depreciation	$ (8,227)	$ (4,655)
Prepaid expenses	(289)	(358)
Other	(293)	(57)
Total deferred tax liabilities	(8,809)	(5,070)
Deferred tax assets
Investment impairment	20,674	30,680
Gift cards	710	969
Deferred revenues	304	355
Accrual for employee benefits and severance	1,166	1,246
Stock option expense	209	55
Investment in partnership	208,167	116,318
Tax Receivable Agreement liability	34,802	7,387
AMT credit	584	1,049
Net operating loss carryforward	16,733	8,512
Claims reserves	420	547
Intangible assets	108	70
Goodwill	996	1,898
Deferred book gain	813	1,337
Other reserves	5,380	5,339
Gross deferred tax assets	291,066	175,762
Valuation allowance	(126,706)	(146,259)
Net deferred tax assets	$ 155,551	$ 24,433