Fair Value of Financial Instruments (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015
Level 2 | Accounts payable and accrued expenses | Interest rate swaps
Fair value of financial assets and liabilities
Fair value of interest rate swaps	$ 2,300,000
Level 2 | Other assets, net | Interest rate swaps
Fair value of financial assets and liabilities
Fair value of interest rate swaps	66,000
Carrying value per balance sheet
Fair value of financial assets and liabilities
Notes receivable issued in connection with property sales	5,400,000	$ 17,900,000
Mortgages payable assumed in connection with acquisitions, net	466,000,000	646,200,000
Notes and bonds payable, net	3,934,400,000	3,618,000,000
Estimated fair value
Fair value of financial assets and liabilities
Notes receivable issued in connection with property sales	5,500,000	19,400,000
Mortgages payable assumed in connection with acquisitions, net	468,700,000	651,500,000
Notes and bonds payable, net	$ 4,143,300,000	$ 3,828,100,000