Contingencies - Guarantees (Details)	9 Months Ended
Sep. 30, 2019 USD ($) extension_option	Dec. 31, 2018 USD ($)
Guarantor Obligations [Line Items]
Obligation Recorded to Reflect Guaranty	$ 977,000	$ 1,158,000
Number of extension options available \| extension_option	1
Shoppes at Eagle Point, LLC
Guarantor Obligations [Line Items]
Maximum Guaranteed Amount	$ 12,740,000
Parkdale Self Storage, LLC
Guarantor Obligations [Line Items]
Company's Ownership Interest (as a percent)	50.00%
Total Outstanding	$ 6,500,000
Maximum guarantee (as a percent)	100.00%
Hamilton Place Self Storage, LLC
Guarantor Obligations [Line Items]
Company's Ownership Interest (as a percent)	54.00%
Total Outstanding	$ 7,002,000
Maximum guarantee (as a percent)	100.00%
West Melbourne I, LLC - Phase I
Guarantor Obligations [Line Items]
Company's Ownership Interest (as a percent)	50.00%
Outstanding Balance	$ 40,002,000
Percentage Guaranteed by the Operating Partnership (as a percent)	50.00%
Maximum Guaranteed Amount	$ 20,001,000
Obligation Recorded to Reflect Guaranty	$ 200,000	203,000
West Melbourne I, LLC - Phase II
Guarantor Obligations [Line Items]
Company's Ownership Interest (as a percent)	50.00%
Outstanding Balance	$ 15,737,000
Percentage Guaranteed by the Operating Partnership (as a percent)	50.00%
Maximum Guaranteed Amount	$ 7,869,000
Obligation Recorded to Reflect Guaranty	$ 79,000	80,000
Port Orange I, LLC
Guarantor Obligations [Line Items]
Company's Ownership Interest (as a percent)	50.00%
Outstanding Balance	$ 54,350,000
Percentage Guaranteed by the Operating Partnership (as a percent)	50.00%
Maximum Guaranteed Amount	$ 27,175,000
Obligation Recorded to Reflect Guaranty	$ 272,000	280,000
Ambassador Infrastructure, LLC
Guarantor Obligations [Line Items]
Company's Ownership Interest (as a percent)	65.00%
Outstanding Balance	$ 10,050,000
Percentage Guaranteed by the Operating Partnership (as a percent)	100.00%
Maximum Guaranteed Amount	$ 10,050,000
Obligation Recorded to Reflect Guaranty	$ 101,000	106,000
Shoppes at Eagle Point, LLC
Guarantor Obligations [Line Items]
Company's Ownership Interest (as a percent)	50.00%
Outstanding Balance	$ 35,189,000
Percentage Guaranteed by the Operating Partnership (as a percent)	35.00%
Maximum Guaranteed Amount	$ 12,740,000
Obligation Recorded to Reflect Guaranty	$ 127,000	364,000
Number of extension options available \| extension_option	1
Option extension term of debt instrument	2 years
EastGate Storage, LLC
Guarantor Obligations [Line Items]
Company's Ownership Interest (as a percent)	50.00%
Outstanding Balance	$ 6,145,000
Percentage Guaranteed by the Operating Partnership (as a percent)	50.00%
Maximum Guaranteed Amount	$ 3,250,000
Obligation Recorded to Reflect Guaranty	$ 33,000	65,000
Reduction of guarantor obligations once construction is complete (as a percent)	50.00%
Reduction of guarantor obligations once certain debt and operational metrics are met (as a percent)	25.00%
Self-Storage at Mid Rivers, LLC
Guarantor Obligations [Line Items]
Company's Ownership Interest (as a percent)	50.00%
Outstanding Balance	$ 5,538,000
Percentage Guaranteed by the Operating Partnership (as a percent)	50.00%
Maximum Guaranteed Amount	$ 2,994,000
Obligation Recorded to Reflect Guaranty	$ 30,000	60,000
Reduction of guarantor obligations once construction is complete (as a percent)	50.00%
Reduction of guarantor obligations once certain debt and operational metrics are met (as a percent)	25.00%
Guaranty fee (as a percent)	1.00%
Parkdale Self Storage, LLC
Guarantor Obligations [Line Items]
Company's Ownership Interest (as a percent)	50.00%
Outstanding Balance	$ 189,000
Percentage Guaranteed by the Operating Partnership (as a percent)	100.00%
Maximum Guaranteed Amount	$ 6,500,000
Obligation Recorded to Reflect Guaranty	$ 65,000	0
Hamilton Place Self Storage, LLC
Guarantor Obligations [Line Items]
Company's Ownership Interest (as a percent)	54.00%
Outstanding Balance	$ 0
Percentage Guaranteed by the Operating Partnership (as a percent)	100.00%
Maximum Guaranteed Amount	$ 7,002,000
Obligation Recorded to Reflect Guaranty	$ 70,000	$ 0
York Town Center Lp
Guarantor Obligations [Line Items]
Company's Ownership Interest (as a percent)	50.00%
Undiscounted maximum exposure	$ 22,000,000
Annual reductions to guarantors obligations	800,000
Guaranteed minimum exposure amount	10,000,000
Guaranteed amount of the outstanding loan based on percentage	$ 12,400,000
Guarantor obligations recoverable (as a percent)	50.00%

The annual reduction amount to the Guarantor's Obligations.

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- Definition

Debt Instrument, Percentage Guaranteed

+ References

No definition available.

+ Details

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- Definition

Debt Instrument, Period of Extension Option

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- Definition

Portion of the loan amount guaranteed by the company based on the guaranty percentage.

+ References

No definition available.

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- Definition

Minimum potential amount of future payments (undiscounted) the company could be required to make under the guarantee or each group of similar guarantees after reductions.

+ References

No definition available.

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- Definition

Guarantor Obligations, Guaranty Fee, Percentage

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No definition available.

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- Definition

Guarantor Obligations, Guaranty Reduction Percentage, Once Certain Debt and Operational Metrics Are Met

+ References

No definition available.

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- Definition

Guarantor Obligations, Guaranty Reduction, Percentage, Once Construction Is Complete

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No definition available.

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- Definition

Percentage of third party construction loan guaranteed by the company.

+ References

No definition available.

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- Definition

Represents amount recoverable by guarantor from third parties for amounts paid under the guaranty.

+ References

No definition available.

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- Definition

Company's maximum guaranteed amount after loans were partially paid down.

+ References

No definition available.

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- Definition

Revenue From Contracts With Customers, Operating Agreements, Number Of Extension Options Available.

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

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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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No definition available.

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- Definition

Maximum potential amount of future payments (undiscounted) the guarantor could be required to make under the guarantee or each group of similar guarantees before reduction for potential recoveries under recourse or collateralization provisions.

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-SubTopic 10
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- Definition

Fair value portion of guarantee, including, but not limited to, financial standby letter of credit, fair value guarantee, guarantee of collection of scheduled contractual cash flows from financial assets, and contracts that contingently require the guarantor to make payments or perform services.

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- Definition

This element represents the current and noncurrent portions of a long-term real estate loan with an initial maturity beyond one year or beyond the normal operating cycle, if longer, to finance building costs. The funds are disbursed as needed or in accordance with a prearranged plan; generally, a portion of the funds is disbursed at inception and the remainder as construction progresses. The money is repaid on completion of the project (generally one to seven years), usually from the proceeds of a mortgage loan. The rate is normally higher than the prime rate, and there is usually an origination fee. The effective yield on these loans tends to be high, and the lender has a security interest in the real property.

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