Summary of Significant Accounting Policies - Schedule of Unpaid Claims Liability (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Tenant Reinsurance Claims:
Unpaid claims liability at beginning of year	$ 3,896	$ 3,908	$ 3,121
Claims and claim adjustment expense for claims incurred in the current year	11,700	7,250	6,421
Claims and claim adjustment expense (benefit) for claims incurred in the prior years	(203)	87	0
Payments for current year claims	(8,895)	(5,423)	(4,283)
Payments for prior year claims	(1,331)	(1,926)	(1,351)
Unpaid claims liability at the end of the year	$ 5,167	$ 3,896	$ 3,908