Fair Value Measurements - Fair Value Disclosures (Details) $ in Thousands	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgages payable, net	$ 92,075	$ 94,155
Unsecured notes payable, net	1,185,479	796,247
Unsecured term loans, net	467,391	716,523
Unsecured revolving line of credit	0	18,000
Fair Value, Level 1
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unsecured notes payable, net	750,908	255,965
Fair Value, Level 3
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgages payable, net	94,078	98,082
Unsecured notes payable, net	454,094	566,918
Unsecured term loans, net	458,788	720,000
Unsecured revolving line of credit	0	18,000
Fair Value, Total
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Mortgages payable, net	94,078	98,082
Unsecured notes payable, net	1,205,002	822,883
Unsecured term loans, net	458,788	720,000
Unsecured revolving line of credit	0	18,000
Unsecured notes payable
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Unsecured notes payable, net	$ 1,200,000	$ 800,000
Discount rate | Unsecured revolving line of credit
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input for measuring debt	0.0165	0.0105
Minimum | Discount rate | Mortgages payable
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input for measuring debt	0.037	0.032
Maximum | Discount rate | Mortgages payable
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input for measuring debt	0.042	0.036
Weighted average | Discount rate | Unsecured notes payable
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input for measuring debt	0.0440	0.0379
Weighted average | Discount rate | Unsecured term loans
Fair Value Measurement Inputs and Valuation Techniques [Line Items]
Input for measuring debt	0.0193	0.0126