Summary of Significant Accounting Policies (Minimum Rental Payments) (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Operating Lease Liabilities, Payments Due [Abstract]
2019 (remainder)	$ 40,456
2020	52,142
2021	47,735
2022	44,463
2023	36,369
Thereafter	154,507
Total	$ 375,672
Real Estate Investments, Net [Abstract]
2019		$ 53,347
2020		51,404
2021		47,237
2022		44,018
2023		35,920
Thereafter		150,226
Total		$ 382,152

Amount of lease payments to be received by lessor for operating lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919396-209981

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Amount of lease payments to be received by lessor in fifth fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest statement of financial position date.

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Amount of lease payments to be received by lessor in fourth year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

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Amount of lease payments to be received by lessor in remainder of fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 30
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=77888428&loc=SL77919396-209981

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Amount of lease payments to be received by lessor after fifth fiscal year following latest statement of financial position date for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

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Amount of lease payments to be received by lessor in third fiscal year following latest fiscal year for operating lease. Excludes interim and annual periods when interim periods are reported on rolling approach, from latest statement of financial position date.

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Future minimum rental payments in aggregate as of the balance sheet date under operating leases.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)
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Future rental payments receivable within the fifth year from the balance sheet date under an operating lease.

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Future rental payments receivable within the third year from the balance sheet date under an operating lease.

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Amount of required minimum rental payments receivable in the remainder of the fiscal year following the latest fiscal year ended for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Future minimum lease payments receivable under operating leases for periods greater than five years following the balance sheet date.

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