Notes Receivable, Net - Schedule of Company's Lending Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Accounts Notes And Loans Receivable [Line Items]
Notes receivable outstanding, beginning of year	$ 2,661
Total loan originations	10,825	$ 2,851
Total principal payments	(11,407)	(166)
Deferred financing fees and costs, net	7	(24)
Notes receivable outstanding, end of year	2,086	2,661
Current portion of notes receivable, net	1,338	1,295
Non-current portion of notes receivable, net	748	1,366
HGC Funded Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loan originations	5,781	2,851
Total transfer of notes to/from senior lenders:	(5,340)
Total principal payments	(1,022)	(166)
Loans Funded With Senior Lender [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loan originations	1,201
Total transfer of notes to/from senior lenders:	1,317
Total principal payments	(2,517)
Loans Funded Within Joint Ventures With Senior Lender [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loan originations	3,843
Total transfer of notes to/from senior lenders:	4,023
Total principal payments	(7,868)
HGC Share of Loan Amount [Member]
Accounts Notes And Loans Receivable [Line Items]
Notes receivable outstanding, beginning of year	2,661
Total loan originations	6,744	2,851
Total transfer of notes to/from senior lenders:	(4,249)
Total principal payments	(3,077)	(166)
Deferred financing fees and costs, net	7	(24)
Notes receivable outstanding, end of year	2,086	2,661
Current portion of notes receivable, net	1,338	1,295
Non-current portion of notes receivable, net	748	1,366
Notes receivable, net, end of year	2,086	2,661
HGC Share of Loan Amount [Member] | HGC Funded Loans [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loan originations	5,781	2,851
Total transfer of notes to/from senior lenders:	(5,340)
Total principal payments	(1,022)	$ (166)
HGC Share of Loan Amount [Member] | Loans Funded With Senior Lender [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loan originations	300
Total transfer of notes to/from senior lenders:	329
Total principal payments	(629)
HGC Share of Loan Amount [Member] | Loans Funded Within Joint Ventures With Senior Lender [Member]
Accounts Notes And Loans Receivable [Line Items]
Total loan originations	663
Total transfer of notes to/from senior lenders:	762
Total principal payments	$ (1,426)