Financial Instruments and Fair Values - Summary of the Carrying and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	$ 13,378	$ 5,591
Carrying Value | Mortgages
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	720,830	759,016
Carrying Value | Exchangeable notes | Senior unsecured notes - exchangeable
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	243,923	241,474
Carrying Value | Senior notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	348,991	348,914
Estimated Fair Value | Mortgages
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	712,365	755,640
Estimated Fair Value | Exchangeable notes | Senior unsecured notes - exchangeable
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	281,068	282,435
Estimated Fair Value | Senior notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	344,267	339,274
Level 1 | Estimated Fair Value | Mortgages
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Level 1 | Estimated Fair Value | Exchangeable notes | Senior unsecured notes - exchangeable
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Level 1 | Estimated Fair Value | Senior notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Level 2 | Estimated Fair Value | Mortgages
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Level 2 | Estimated Fair Value | Exchangeable notes | Senior unsecured notes - exchangeable
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	281,068	282,435
Level 2 | Estimated Fair Value | Senior notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Level 3 | Estimated Fair Value | Mortgages
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	712,365	755,640
Level 3 | Estimated Fair Value | Exchangeable notes | Senior unsecured notes - exchangeable
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Level 3 | Estimated Fair Value | Senior notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	344,267	339,274
Unsecured term loan facility | Carrying Value | Term loan facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	263,546	262,927
Unsecured term loan facility | Estimated Fair Value | Term loan facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	265,000	265,000
Unsecured term loan facility | Level 1 | Estimated Fair Value | Term loan facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Unsecured term loan facility | Level 2 | Estimated Fair Value | Term loan facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	0	0
Unsecured term loan facility | Level 3 | Estimated Fair Value | Term loan facility
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, fair value	265,000	265,000
Interest Rate Swap
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in accounts payable and accrued expenses	13,400
Interest Rate Swap | Carrying Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in prepaid expenses and other assets	0	614
Interest rate swaps included in accounts payable and accrued expenses	13,378	5,591
Interest Rate Swap | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in prepaid expenses and other assets	0	614
Interest rate swaps included in accounts payable and accrued expenses	13,378	5,591
Interest Rate Swap | Level 1 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in prepaid expenses and other assets	0	0
Interest rate swaps included in accounts payable and accrued expenses	0	0
Interest Rate Swap | Level 2 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in prepaid expenses and other assets	0	614
Interest rate swaps included in accounts payable and accrued expenses	13,378	5,591
Interest Rate Swap | Level 3 | Estimated Fair Value
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate swaps included in prepaid expenses and other assets	0	0
Interest rate swaps included in accounts payable and accrued expenses	$ 0	$ 0