Loans Receivable - Summary of Real Estate Loan Activity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Advances on loans receivable:
Net cash advances on loans receivable	$ 43,148	$ 10,441
Receipts on loans receivable:
Net cash receipts on loans receivable	2,852	10,045
Seniors Housing Operating
Advances on loans receivable:
Investments in new loans	30,999	0
Draws on existing loans	12,149	10,441
Net cash advances on loans receivable	43,148	10,441
Receipts on loans receivable:
Loan payoffs	1,620	0
Principal payments on loans	1,232	10,045
Net cash receipts on loans receivable	2,852	10,045
Net cash advances (receipts) on loans receivable	$ 40,296	$ 396