Basis of Presentation (Narrative) (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2018 USD ($)
General and Administrative Expense
Basis of Presentation [Line Items]
Unincorporated business tax	$ (1,100)
Income Tax Expense
Basis of Presentation [Line Items]
Unincorporated business tax	1,100
Lease revenues
Basis of Presentation [Line Items]
Property rentals	440,110
Tenant expense reimbursement	$ 60,310