Variable Interest Entities - Summarized Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Assets:
Net Investment in Real Estate	$ 3,013,435	$ 2,861,860
Total Assets	3,376,725	3,142,691
Liabilities and Partners' Capital:
Mortgage Loans Payable, Net	180,313	296,470
Total Liabilities and Equity/Partners' Capital	3,376,725	3,142,691
Other Real Estate Partnerships
Assets:
Net Investment in Real Estate	257,318	260,528
Other Assets, Net	37,870	25,059
Total Assets	295,188	285,587
Liabilities and Partners' Capital:
Mortgage Loans Payable, Net	11,089	20,497
Other Liabilities, Net	21,423	9,045
Partners' Capital	262,676	256,045
Total Liabilities and Equity/Partners' Capital	$ 295,188	$ 285,587