Variable Interest Entities - Summarized Balance Sheet (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Assets:
Net Investment in Real Estate	$ 2,651,995	$ 2,588,422
Total Assets	2,863,963	2,793,263
Liabilities and Partners' Capital:
Mortgage Loans Payable, Net	455,016	495,956
Total Liabilities and Equity/Partners' Capital	2,863,963	2,793,263
Other Real Estate Partnerships
Assets:
Net Investment in Real Estate	281,816	278,398
Other Assets, Net	23,072	24,401
Total Assets	304,888	302,799
Liabilities and Partners' Capital:
Mortgage Loans Payable, Net	61,911	70,366
Other Liabilities, Net	9,130	9,138
Partners’ Capital	233,847	223,295
Total Liabilities and Equity/Partners' Capital	$ 304,888	$ 302,799