Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Level 2 | Interest rate swaps | Accounts payable and accrued expenses
Fair value of financial assets and liabilities
Fair value of derivative liabilities	$ 162
Level 2 | Interest rate swaps | Other assets, net
Fair value of financial assets and liabilities
Fair value of derivative assets	4,600
Mortgages Payable
Fair value of financial assets and liabilities
Unamortized balance of non-cash net premiums	4,700	$ 5,900
Deferred financing costs	196	236
Notes and bonds payable
Fair value of financial assets and liabilities
Unamortized balance of original issuance premiums	10,800	14,300
Deferred financing costs	35,000	34,100
Carrying value
Fair value of financial assets and liabilities
Notes receivable issued in connection with property sales		5,300
Mortgages payable assumed in connection with acquisitions	305,700	320,300
Notes and bonds payable	5,400,000	5,250,000
Estimated fair value
Fair value of financial assets and liabilities
Notes receivable issued in connection with property sales		5,300
Mortgages payable assumed in connection with acquisitions	310,500	334,200
Notes and bonds payable	$ 5,397,600	$ 5,475,300