Income Taxes - Statutory Federal Income Tax (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Effective income tax rate reconciliation at federal statutory income tax rate, amount	$ (195)	$ (73)	$ (65)
State and local taxes, net of federal benefit	(77)	(10)	(11)
Other	(1,312)	(1,296)	(1,652)
Benefit (provision) for income taxes	$ (1,584)	$ (1,379)	$ (1,728)
Effective income tax rate reconciliation, at federal statutory income tax rate (in percent)	21.00%	21.00%	21.00%