Fair Value of Financial Instruments - Summary of Carrying Value and Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Mortgages Payable And Notes Payable | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value of long-term debt	$ 761,979	$ 823,045
Mortgages Payable And Notes Payable | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value of long-term debt	779,867	833,931
Senior Notes And Debentures | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value of long-term debt	1,975,988	1,732,551
Senior Notes And Debentures | Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Fair value of long-term debt	$ 2,153,692	$ 1,786,758