Income Taxes - Provision and Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Current - Federal	$ (5,431)	$ 0	$ 0
Current - State	1,713	1,631	1,435
Current - Foreign	670	2,380	200
Current tax	(3,048)	4,011	1,635
Deferred:
Deferred - Foreign	(236)	9	(69)
Deferred tax	(236)	9	(69)
Income tax provision (benefit)	(3,284)	$ 4,020	$ 1,566
Tax Cuts and Jobs Act of 2017, provisional income tax benefit	$ 5,431
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Taxes at statutory U.S. federal income tax rate	35.00%	35.00%	35.00%
Nontaxable income of HPT	(35.00%)	(35.00%)	(35.00%)
Minimum Tax Credit Refund	(2.60%)	(0.00%)	(0.00%)
State and local income taxes, net of federal tax benefit	0.80%	0.80%	0.80%
Foreign taxes	0.30%	1.00%	0.10%
Tax Act adjustment	21.80%	0.00%	0.00%
Change in valuation allowance	(23.50%)	0.80%	3.70%
Other differences, net	1.60%	(0.80%)	(3.70%)
Effective tax rate	(1.60%)	1.80%	0.90%