Loans Receivable and Investments (Details) $ in Thousands	1 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) loan	Dec. 31, 2014 USD ($) loan	Dec. 31, 2013 USD ($)	Aug. 17, 2015 USD ($) loan
Loans Receivable And Investments [Abstract]
Net loans receivable and investments relating to seniors housing and healthcare operators or properties		$ 895,000	$ 896,500
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loans, unsecured loans, and other available-for-sale securities, carrying amount		895,038	896,547
Secured loans, unsecured loans, and other available-for-sale securities, amortized cost		893,489	889,763
Secured loans, unsecured loans, and other available-for-sale securities, fair value		919,334	907,061
Unrealized Gain (Loss)		1,549	6,784
Proceeds from sale of loans		97,000	55,900
Gain on the repayment of loans receivable		1,900	5,200
Investment in loans receivable and other		171,144	498,992	$ 37,963
Purchase of marketable securities		0	96,689	$ 0
Total proceeds from sale or maturity of marketable securities			22,300
Recognized gain on sale of marketable securities			600
Secured Loans Receivable and Investments, Net
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loans, unsecured loans, and other available-for-sale securities, carrying amount		857,112	802,881
Secured loans, unsecured loans, and other available-for-sale securities, amortized cost		855,563	801,143
Secured loans, unsecured loans, and other available-for-sale securities, fair value		880,528	811,957
Unrealized Gain (Loss)		1,549	1,738
Other assets
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured loans, unsecured loans, and other available-for-sale securities, carrying amount		37,926	93,666
Secured loans, unsecured loans, and other available-for-sale securities, amortized cost		37,926	88,620
Secured loans, unsecured loans, and other available-for-sale securities, fair value		38,806	95,104
Unrealized Gain (Loss)		0	5,046
Government-sponsored pooled loan investments
Accounts, Notes, Loans and Financing Receivable [Line Items]
Marketable securities		63,679	63,115
Available-for-sale securities, amortized cost basis		62,130	61,377
Unrealized Gain (Loss)		1,549	1,738
Investment in loans receivable and other			38,700
Marketable securities
Accounts, Notes, Loans and Financing Receivable [Line Items]
Marketable securities			76,046
Available-for-sale securities, amortized cost basis			71,000
Unrealized Gain (Loss)			5,046
Senior unsecured corporate bonds
Accounts, Notes, Loans and Financing Receivable [Line Items]
Carrying value of investment	$ 71,000
Proceeds from sale of investment	$ 76,800
Recognized gain on sale of investments		5,800
Unrealized gains of investments			5,000
Purchase of marketable securities			71,000
Marketable equity securities
Accounts, Notes, Loans and Financing Receivable [Line Items]
Purchase of marketable securities			21,700
Secured mortgage loans and other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured mortgage loans and other,, carrying amount and amortized cost		793,433	739,766
Secured mortgage loans and other, fair value		816,849	$ 748,842
Unrealized Gain (Loss)		$ 0
Number of loans sold | loan		3	3
Secured mortgage loans and other | Spin-off
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans receivable | loan					2
Carrying amounts of loans contributed in CCP spin-off					$ 26,900
Loans receivable for sale			$ 26,900
Secured mortgage loans and other | Mezzanine Loan Investment Due 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Investment in loans receivable and other			$ 425,000
Secured loan receivable, interest rate			8.10%
Non-mortgage loans receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Secured mortgage loans and other,, carrying amount and amortized cost		$ 37,926	$ 17,620
Secured mortgage loans and other, fair value		38,806	$ 19,058
Unrealized Gain (Loss)		$ 0
Number of loans sold | loan		1	2
Non-mortgage loans receivable | Spin-off
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans receivable | loan					7
Carrying amounts of loans contributed in CCP spin-off					$ 4,200
Loans receivable for sale			$ 4,300
Secured Debt
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | loan		1
Debt instrument, face amount		$ 78,400
Non-mortgaged
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans | loan		1
Debt instrument, face amount		$ 20,000