Notes Payable, Revolving Credit Facility, Interest and Amortization of Deferred Debt Costs - Scheduled Maturities of Debt, Including Scheduled Principal Amortization (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Balloon Payments
July 1 through December 31, 2020	$ 0
2021	11,012
2022	211,002
2023	84,225
2024	66,164
2025	20,363
Thereafter	532,910
Principal amount	925,676
Scheduled Principal Amortization
July 1 through December 31, 2020	14,167
2021	28,996
2022	29,609
2023	30,021
2024	29,326
2025	26,291
Thereafter	99,518
Principal amount	257,928
Total
July 1 through December 31, 2020	14,167
2021	40,008
2022	240,611
2023	114,246
2024	95,490
2025	46,654
Thereafter	632,428
Principal amount	1,183,604	$ 1,100,000
Unamortized deferred debt costs	9,037	9,700
Net	1,174,567
Debt Instrument [Line Items]
Outstanding line of credit	173,642	86,371
Unsecured Revolving Credit Facility
Debt Instrument [Line Items]
Outstanding line of credit	$ 174,500	$ 87,500

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of 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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Amount of payment greater than the preceding installment payments to be paid at final maturity date of debt.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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