Variable Interest Entities - Summarized Balance Sheet (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Assets:
Net Investment in Real Estate	$ 2,973,831	$ 2,861,860
Total Assets	3,254,901	3,142,691
Liabilities and Partners' Capital:
Mortgage Loans Payable, Net	221,357	296,470
Total Liabilities and Equity/Partners' Capital	3,254,901	3,142,691
Other Real Estate Partnerships
Assets:
Net Investment in Real Estate	255,559	260,528
Other Assets, Net	23,742	25,059
Total Assets	279,301	285,587
Liabilities and Partners' Capital:
Mortgage Loans Payable, Net	13,164	20,497
Other Liabilities, Net	7,520	9,045
Partners' Capital	258,617	256,045
Total Liabilities and Equity/Partners' Capital	$ 279,301	$ 285,587