Loans Receivable and Other Lending Investments, net (Schedule of Loans Receivable) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	May 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross carrying value of loans	$ 703,279		$ 919,493
Reserves for loan losses	(28,634)		(53,395)		$ (78,489)	$ (85,545)
Total loans receivable, net	674,645		866,098
Other lending investments	153,216		122,126
Total loans receivable and other lending investments, net	827,861		988,224
Purchase price for properties acquired from lessee	44,300	$ 44,100
Senior mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross carrying value of loans	572,584		760,749
Corporate/Partnership loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross carrying value of loans	119,818		148,583
Subordinate mortgages
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross carrying value of loans	$ 10,877		$ 10,161
Nonperforming Financial Instruments \| Corporate/Partnership loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total gross carrying value of loans				$ 145,800