Loans Receivables and Investments (Details) 2 - USD ($) $ in Thousands	Dec. 31, 2020	Jul. 31, 2020	Apr. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss	$ (26,469)			$ 0
Debt Securities, Available-for-sale	237,553			237,360
Non-mortgage loans receivable, net	57,077			63,724
Secured loans, unsecured loans, and other available-for-sale securities, amortized cost	899,028			974,510
Secured Loans, Unsecured Loans And Other Available-For-Sale Securities, Unrealized gain	27,638			31,186
Total loans receivable and investments, net	900,197			1,005,696
Secured loans, unsecured loans, and other available-for-sale securities, fair value	852,996			1,006,889
Brookdale Senior Living
Accounts, Notes, Loans and Financing Receivable [Line Items]
Non-mortgage loans receivable, net		$ 45,000
Non-mortgage loans receivable, net
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(17,623)			0
Non-mortgage loans receivable, amortized cost	74,700			63,724
Non-mortgage loans receivable, net, unrealized gain	0			0
Non-mortgage loans receivable, net	57,077			63,724
Non-mortgage loans receivable, fair value	57,009			63,538
Secured/mortgage loans and other, net
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt Securities, Held-to-maturity	555,840			645,546
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0			0
Debt Securities, Held-to-maturity, Accumulated Unrecognized Gain	0			0
Debt Securities, Held-to-maturity, Fair Value	508,707			646,925
Secured/mortgage loans and other, net | Holiday Management Company Member
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt Securities, Held-to-maturity			$ 66,000
Secured/mortgage loans and other, net | Brookdale Senior Living
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt Securities, Held-to-maturity		$ 78,000
Government-sponsored pooled loan investments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(8,846)			0
Debt Securities, Available-for-sale, Amortized Cost	55,154			52,178
Available-for-sale securities, unrealized gain (loss)	3,419			6,888
Debt Securities, Available-for-sale	49,727			59,066
Total investments reported as secured loans receivable and investments, net
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss	(8,846)			0
Available-for-sale securities, unrealized gain (loss)	3,419			6,888
Debt securities, available-for-sale and held-to-maturity, amortized cost	610,994			697,724
Debt securities, available-for-sale and held-to-maturity, carrying amount	605,567			704,612
Debt securities, Held-to-Maturity and Available-for-Sale, Fair Value	558,434			705,991
Senior Unsecured Notes
Accounts, Notes, Loans and Financing Receivable [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss	0			0
Debt Securities, Available-for-sale, Amortized Cost	213,334			213,062
Available-for-sale securities, unrealized gain (loss)	24,219			24,298
Debt Securities, Available-for-sale	$ 237,553			$ 237,360