Loans Receivable (Summary of Loan Activity) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Advances on loans receivable:
Investments in new loans	$ 46,824	$ 77,289	$ 61,122
Draws on existing loans	72,875	34,759	40,094
Net cash advances on loans receivable	119,699	112,048	101,216
Receipts on loans receivable:
Loan payoffs	118,703	144,700	181,549
Principal payments on loans	9,003	59,235	33,431
Net cash receipts on loans	127,706	203,935	214,980
Net cash advances (receipts) on loans	$ (8,007)	$ (91,887)	$ (113,764)