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Real Estate and Intangible Assets - Business Combinations and Asset Acquisitions (Details) - USD ($) $ in Thousands | 6 Months Ended
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Jun. 30, 2018 | Jun. 30, 2017
Business Acquisition [Line Items] |  |
Total Purchase Price | $ 14,341 |
Asset Acquisitions |  |
Business Acquisition [Line Items] |  |
Discount on Assumed Debt | 0 | $ 399
Total Purchase Price |  | 15,697
Asset Acquisitions | Customer relationships |  |
Business Acquisition [Line Items] |  |
Assets Acquired | 566 | 1,256
Asset Acquisitions | Above market leases |  |
Business Acquisition [Line Items] |  |
Assets Acquired | 49 | 0
Asset Acquisitions | Below Market Leases |  |
Business Acquisition [Line Items] |  |
Fair Value of Interest Rate Swap Assumed | 0 | (1,030)
Asset Acquisitions | Land |  |
Business Acquisition [Line Items] |  |
Assets Acquired | 459 | 1,996
Asset Acquisitions | Building |  |
Business Acquisition [Line Items] |  |
Assets Acquired | 11,609 | 9,975
Asset Acquisitions | Tenant Improvements |  |
Business Acquisition [Line Items] |  |
Assets Acquired | 615 | 905
Asset Acquisitions | In-place Leases |  |
Business Acquisition [Line Items] |  |
Assets Acquired | 509 | 1,690
Asset Acquisitions | Leasing Costs |  |
Business Acquisition [Line Items] |  |
Assets Acquired | $ 534 | $ 464

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