Loans Receivable - Summary of Real Estate Loan Activity (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Advances on loans receivable:
Net cash advances on loans receivable	$ 19,538	$ 65,422
Receipts on loans receivable:
Net cash receipts on loans receivable	12,796	8,660
Seniors Housing Operating
Advances on loans receivable:
Investments in new loans	2,477	30,000
Draws on existing loans	17,061	35,422
Net cash advances on loans receivable	19,538	65,422
Receipts on loans receivable:
Loan payoffs	0	4,384
Principal payments on loans	12,796	4,276
Net cash receipts on loans receivable	12,796	8,660
Net cash advances (receipts) on loans receivable	$ 6,742	$ 56,762