Real Estate Loans, Notes Receivable, and Lines of Credit Interest income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Receivables [Abstract]
interest revenue current pay	$ 30,985	$ 31,368	$ 32,570
Accrued exit fee revenue	13,663	19,003	18,670
Deferred Revenue, Revenue Recognized	1,426	1,570	1,376
amortization of purchase option termination fee income	9,111	9,820	0
Debt Instrument, Debt Default Interest, Amount	91	64
Net loan fee revenue	55,276	61,825	52,616
interest revenue notes receivable	5,430	3,784	4,286
Interest Income, Money Market Deposits	687	147	0
Interest Income, Securities, Mortgage Backed	95	50	0
Interest income on loans and notes receivable	$ 61,488	$ 65,806	$ 56,902