Organization and Principles of Consolidation Revenues and Tenant and Other Receivables (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Schedule of management, transaction, and other fees [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets			$ 30,903
Parent Company [Member]
Schedule of management, transaction, and other fees [Line Items]
Accounts Receivable, Net	$ 159,587		170,985
Management Fees Revenue	7,158	$ 6,706
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets			30,903
Parent Company [Member] | Other transaction fees [Member]
Schedule of management, transaction, and other fees [Line Items]
Management Fees Revenue	1,002	670
Parent Company [Member] | Management, transaction, and other fee [Member]
Schedule of management, transaction, and other fees [Line Items]
Accounts Receivable, Net	9,300		$ 8,700
Parent Company [Member] | Property management services [Member]
Schedule of management, transaction, and other fees [Line Items]
Management Fees Revenue	3,768	3,418
Parent Company [Member] | Asset management services [Member]
Schedule of management, transaction, and other fees [Line Items]
Management Fees Revenue	1,703	1,789
Parent Company [Member] | Leasing services [Member]
Schedule of management, transaction, and other fees [Line Items]
Management Fees Revenue	685	$ 829
Accounting Standards Update 2017-05 [Member]
Schedule of management, transaction, and other fees [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	$ 30,900