Fair Value Measurements - Fair Value Disclosures (Details) $ in Thousands	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Fair Value Measurements [Line Items]
Mortgages payable, net	$ 94,155	$ 205,320
Unsecured notes payable, net	796,247	696,362
Unsecured term loans, net	716,523	447,367
Unsecured revolving line of credit	18,000	273,000
Fair value, Level 1
Fair Value Measurements [Line Items]
Unsecured notes payable, net	255,965	235,788
Fair value, Level 3
Fair Value Measurements [Line Items]
Mortgages payable, net	98,082	208,173
Unsecured notes payable, net	566,918	435,704
Unsecured term loans, net	720,000	449,266
Unsecured revolving line of credit	18,000	272,553
Fair value, Total
Fair Value Measurements [Line Items]
Mortgages payable, net	98,082	208,173
Unsecured notes payable, net	822,883	671,492
Unsecured term loans, net	720,000	449,266
Unsecured revolving line of credit	18,000	272,553
Unsecured notes payable
Fair Value Measurements [Line Items]
Unsecured notes payable, net	$ 800,000	$ 700,000
Discount rate \| Unsecured revolving line of credit
Fair Value Measurements [Line Items]
Input for measuring debt	0.0105	0.0110
Discount rate \| Minimum \| Mortgages payable
Fair Value Measurements [Line Items]
Input for measuring debt	0.032	0.042
Discount rate \| Maximum \| Mortgages payable
Fair Value Measurements [Line Items]
Input for measuring debt	0.036	0.044
Discount rate \| Weighted average \| Unsecured notes payable
Fair Value Measurements [Line Items]
Input for measuring debt	0.0379	0.0491
Discount rate \| Weighted average \| Unsecured term loans
Fair Value Measurements [Line Items]
Input for measuring debt	0.0126	0.0125

Value of input used to measure debt instrument, including, but not limited to, convertible and non-convertible debt.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Including the current and noncurrent portions, aggregate carrying amount of all types of notes payable, as of the balance sheet date, with initial maturities beyond one year or beyond the normal operating cycle, if longer.

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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of uncollateralized debt obligations (with maturities initially due after one year or beyond the operating cycle if longer).

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