Fair Value of Financial Instruments (Details Textual) $ in Thousands	3 Months Ended
Mar. 31, 2019 USD ($)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate cash flow hedge reclassified as non-cash increase to interest expense in the next 12 months	$ 787
Weighted Average
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Interest rate	4.10%
Significant Unobservable Inputs (Level 3)
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of note payable	$ 87,000
Senior Notes \| Significant Unobservable Inputs (Level 3) \| Senior Notes Due 2027
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long term debt	232,500
Senior Notes \| Significant Unobservable Inputs (Level 3) \| Senior Notes Due 2026
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long term debt	184,700
Senior Notes \| Significant Other Observable Inputs (Level 2) \| Senior Notes Due 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long term debt	241,300
Senior Notes \| Significant Other Observable Inputs (Level 2) \| Senior Notes Due 2023
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of long term debt	$ 259,500

Interest rate of mortgage loan within investment in mortgage loan on real estate by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 12
-Paragraph Column B
-Subsection 29

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 948
-SubTopic 310
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column B))
-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

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- Definition

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+ References

No definition available.

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- Definition

The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=112277219&loc=d3e80748-113994

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- Definition

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

+ References

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Fair value portion of notes payable.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20,22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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