Real Estate Loans Receivable (Details 1) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Summary of allowance for losses on loans receivable
Balance at beginning of year		$ 6,563	$ 0	$ 0
Allowance for loan losses	[1]	62,966	6,935	0
Change in present value		(1,157)	(372)	0
Balance at end of year		68,372	6,563	0
Summary of loan impairments
Balance of impaired loans at end of year					$ 282,882	$ 377,549	$ 0
Allowance for loan losses related to three Genesis real estate loans		68,372	0	0	68,372	6,563	0
Balance of impaired loans not reserved					$ 214,510	$ 370,986	$ 0
Average impaired loans for the year		330,216	188,775	10,500
Interest recognized on impaired loans	[2]	$ 27,793	$ 8,707	$ 0

[1] Excludes direct write down of an impaired loan receivable in 2016.

[2] Represents cash interest recognized in the period since loans were identified as impaired.