Fair Value Measurements (Narrative) (Details)	9 Months Ended
Sep. 30, 2018 USD ($) property	Dec. 31, 2017 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of fixed rate mortgage loans payable	$ 45,200,000	$ 127,700,000
Carrying value of fixed rate mortgage payable	$ 47,500,000	128,000,000
Number of properties \| property	58
Real estate held for sale	$ 11,348,000
Nonrecurring Basis [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets measured at fair value		$ 0
Nonrecurring Basis [Member] \| Level 3 [Member] \| Assets [Member] \| Retail Properties [Member] \| Income Capitalization Approach [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Number of properties \| property	1
Real estate held for sale	$ 1,600,000
Nonrecurring Basis [Member] \| Level 3 [Member] \| Assets [Member] \| Retail Properties [Member] \| Income Capitalization Approach [Member] \| Measurement Input Cap Rate [Member] \| Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Capitalization rates	8.50%

Fair value capitalization rate.

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Amount classified as assets attributable to disposal group held for sale or disposed of.

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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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Fair value portion of contractual obligation to pay money on demand or on fixed or determinable dates.

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

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The number of real estate properties owned as of the balance sheet date.

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