SCHEDULE IV - MORTGAGE LOANS ON REAL ESTATE - Mortgage Loan Activity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Movement in Mortgage Loans on Real Estate
Balance, beginning of period	$ 83,248	$ 81,056	$ 75,740
Additions during period:
New loans	39,592	74,234	76,316
Other - deferral for collection of commitment fees, net of costs	802	1,587	1,706
Other - deferral for collection of commitment fees, net of costs	1,303	1,026	676
Deductions during period:
Collections of principal	(13,886)	(16,468)	(17,557)
Foreclosures	(241)	0	(127)
Cost of mortgages sold, net	(42,663)	(57,947)	(54,973)
Other - reclassification from secured borrowings	0	0	(534)
Other - bad debt expense	(76)	(240)	(191)
Balance, end of period	$ 68,079	$ 83,248	$ 81,056