Income Taxes - NOL Carryforwards (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 463,500,000
Valuation allowance offsetting the deferred tax assets	$ 125,528,000	$ 118,283,000
Amount of tax with-held		$ 292,000
Percentage of tax withholding	5.00%
Interest on tax	$ 23,000
SPAIN
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	98,200,000
Other non-U.S. Countries
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	194,000,000
US
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	82,600,000
Velardena Properties | Mexico
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	75,700,000
Other Mexico activities | Mexico
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards	$ 13,000,000