Organization, Basis of Presentation and Summary of Significant Accounting Policies (Details Textual) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($) segment	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Operating leases, remaining contractual payments under ground lease agreements	$ 41,451
Taxable income minimum distribution portion not subject to federal taxation, percentage	90.00%
Capitalized costs related to the improvement or replacement of real estate properties	$ 10,600	$ 8,900
Allowance for doubtful accounts	6,400		$ 6,400
Payroll related costs capitalized	$ 334	$ 312
Number of reportable segments | segment	1
Minimum | Building
Property, Plant and Equipment [Line Items]
Useful life of PPE (in years)	39 years
Minimum | Property Improvements
Property, Plant and Equipment [Line Items]
Useful life of PPE (in years)	10 years
Minimum | Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Useful life of PPE (in years)	3 years
Maximum | Building
Property, Plant and Equipment [Line Items]
Useful life of PPE (in years)	40 years
Maximum | Property Improvements
Property, Plant and Equipment [Line Items]
Useful life of PPE (in years)	20 years
Maximum | Furniture and Fixtures
Property, Plant and Equipment [Line Items]
Useful life of PPE (in years)	10 years