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Dividends characterized as return of capital percentage.

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Percentage of ordinary taxable income distributed to stockholders.

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Rental revenue percentage.

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Revenue recognized rent.

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Significant accounting policies.

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Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

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The aggregate expense charged against earnings to allocate the cost of intangible assets (nonphysical assets not used in production) in a systematic and rational manner to the periods expected to benefit from such assets. As a noncash expense, this element is added back to net income when calculating cash provided by or used in operations using the indirect method.

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The amount of cash deposited in financial institutions as of the balance sheet date that is insured by the Federal Deposit Insurance Corporation.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

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Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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Amount of expense related to write-down of receivables to the amount expected to be collected. Includes, but is not limited to, accounts receivable and notes receivable.

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Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

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Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Significant Accounting Policies [Line Items]
Federal Deposit Insurance Corporation deposit insurance limit per institution	$ 250,000
Restricted cash	4,634,000	$ 5,518,000
Bad debt expense	870,000	975,000	$ 746,000
Amortization expense for intangible assets	1,536,000	3,735,000	7,206,000
Amortization expense for intangible assets expected for 2018	1,024,000
Amortization expense for intangible assets expected for 2019	10,000
Amortization expense for intangible assets expected for 2020	10,000
Amortization expense for intangible assets expected for 2021	10,000
Amortization expense for intangible assets expected for 2022	10,000
Amortization expense for intangible assets expected thereafter	35,000
Depreciation expense	32,665,000	31,089,000	20,888,000
Advertising expenses	1,806,000	1,749,000	1,399,000
Income tax expense	$ 0	$ 0	$ 0
Taxable income distributable to stockholders	90.00%
Dividends characterized as capital gain distribution	53.00%	93.00%
Dividends characterized as ordinary income percentage	36.00%
Dividends characterized as return of capital	11.00%	7.00%	83.00%
Dividends characterized as ordinary taxable income			17.00%
Natural Disasters and Other Insurable Events
Significant Accounting Policies [Line Items]
Rent revenue recognized	$ 110,000	$ 189,000
North Carolina
Significant Accounting Policies [Line Items]
Percentage of rental revenue	14.70%
Tennessee
Significant Accounting Policies [Line Items]
Percentage of rental revenue	13.09%
Kentucky
Significant Accounting Policies [Line Items]
Percentage of rental revenue	11.51%
Texas
Significant Accounting Policies [Line Items]
Percentage of rental revenue	9.95%
South Carolina
Significant Accounting Policies [Line Items]
Percentage of rental revenue	9.09%
South Carolina
Significant Accounting Policies [Line Items]
Percentage of rental revenue	8.61%
Oklahoma
Significant Accounting Policies [Line Items]
Percentage of rental revenue	7.86%
Building and Building Improvements
Significant Accounting Policies [Line Items]
Depreciable Lives	40 years
Leases Acquired In Place
Significant Accounting Policies [Line Items]
Acquisition of above-market in-place leases	$ 2,515,000	$ 0
Minimum \| Equipment and Fixtures
Significant Accounting Policies [Line Items]
Depreciable Lives	5 years
Maximum
Significant Accounting Policies [Line Items]
Cash And Cash Equivalents Maturity Period	3 months
Maximum \| Equipment and Fixtures
Significant Accounting Policies [Line Items]
Depreciable Lives	10 years