Real Estate Investments (Details Textual) $ in Thousands, ft² in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017 USD ($) ft²	Sep. 30, 2017 USD ($) ft²	Dec. 31, 2016 USD ($) ft²
Real Estate Properties [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Land	$ 58,700	$ 58,700
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Buildings	123,400	123,400
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	57,400	57,400
Proceeds from Sale of Real Estate	7,500	29,400
Gains (Losses) on Sales of Investment Real Estate	$ 500	$ 10,000
Number of Real Estate Properties	425	425	366
Land Subject to Ground Leases \| ft²	8.3	8.3	7.0
Real Estate Investment Property, Net, Total	$ 1,121,026	$ 1,121,026	$ 950,261
Five Development And PCS Projects [Member]
Real Estate Properties [Line Items]
Property Subject to or Available for Operating Lease, Gross	35,900	35,900
Nine Development And PCS Projects [Member]
Real Estate Properties [Line Items]
Property Subject to or Available for Operating Lease, Gross	57,300	57,300
Fourteen Retail Net Lease Assets [Member]
Real Estate Properties [Line Items]
Payments to Acquire Property, Plant, and Equipment	$ 55,100
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (in year)	11 years 2 months 12 days
Sixty One Retail Net Lease Assets [Member]
Real Estate Properties [Line Items]
Payments to Acquire Property, Plant, and Equipment		$ 239,500
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life (in year)		11 years 10 months 24 days

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

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Amount of facility held for productive use including, but not limited to, office, production, storage and distribution facilities, acquired at the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 20
-Section 50
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Amount of intangible assets, excluding goodwill, acquired at the acquisition date.

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Amount of real estate acquired, at the acquisition date.

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The net gain (loss) resulting from sales and other disposals of real estate owned for investment purposes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
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Area of land subject to a ground lease.

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

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The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.

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Cash received for the sale of real estate that is not part of an investing activity during the current period.

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Amount before accumulated depreciation of physical assets used in the normal conduct of business to produce goods and services subject to or available for lease.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Amount of real estate investment property, net of accumulated depreciation, which may include the following: (1) land available-for-sale; (2) land available-for-development; (3) investments in building and building improvements; (4) tenant allowances; (5) developments in-process; (6) rental properties; and (7) other real estate investments.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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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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