Loans Payable and Secured Line of Credit - Interest (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Loans Payable and Secured Line of Credit
Interest expense	$ 4,418	$ 3,525	$ 12,554	$ 9,905
Interest capitalized	(3,820)	(3,525)	(11,702)	(9,905)
Interest income	(53)	(14)	(57)	(53)
Interest expense (income), net	$ 545	$ (14)	$ 795	$ (53)