Income Taxes - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Deferred tax assets:
Tax loss carryforwards	$ 42,940	$ 44,285
Other	3,175	3,612
Deferred tax assets, gross	46,115	47,897
Valuation allowance	(46,115)	(47,897)
Deferred income tax assets, net	0	0
Deferred tax liabilities:
Property basis difference	(6,682)	(6,996)
Puerto Rico deferred tax gain	(13,850)	0
Net deferred tax liabilities	$ (20,532)	$ (6,996)