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Area of land held.

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Area of a real estate property.

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Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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Amount, after allowance for credit loss, of financing receivable, classified as current. Includes, but is not limited to, notes and loan receivable.

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Note 3 - Equity Method and Other Investments and Related Commitments and Contingent Liabilities, Including Guarantees (Details Textual)	3 Months Ended		12 Months Ended
	Mar. 31, 2019 USD ($) a	Mar. 31, 2018 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 1992 a
Operating Leases, Rent Expense, Total	$ 7,800	$ 7,500
Equity Method Investments	811,384		$ 881,860
Financing Receivable, after Allowance for Credit Loss, Current, Total	218,158		218,158
Other Long-term Investments	$ 1,691,116		1,689,249
OKC Industrial Properties [Member]
Area of Land \| a	46					260
Broadway Sixty-Eight Partnership [Member]
Equity Method Investment, Ownership Percentage	33.00%
Equity Method Investments	$ 182,687		172,722
Grand Woods Development, LLC [Member]
Equity Method Investment, Ownership Percentage	47.00%
Equity Method Investments	$ 360,408		438,303
Area of Real Estate Property \| a	26.56
Loan Guaranteed	$ 1,000,000
Loans Payable, Total	1,595,750
Financing Receivable, after Allowance for Credit Loss, Current, Total	$ 43,158
QSN Office Park [Member]
Equity Method Investment, Ownership Percentage	20.00%
Equity Method Investments	$ 268,289		270,835
Loan Guaranteed	$ 1,300,000
OKC Industrial Properties [Member]
Other Investment, Ownership Percentage	10.00%
Other Long-term Investments	$ 56,164		56,164
Bailey [Member]
Other Investment, Ownership Percentage	10.00%
Other Long-term Investments	$ 80,377		80,377
Cloudburst Solutions [Member]
Financing Receivable, after Allowance for Credit Loss, Current, Total	$ 175,000
Other Investment, Ownership Percentage	10.625%
Other Long-term Investments	$ 1,294,375		1,294,375
Payments to Acquire Interest in Subsidiaries and Affiliates, Total			44,375	$ 750,000	$ 500,000
Ocean [Member]
Other Investment, Ownership Percentage	12.44%
Other Long-term Investments	$ 219,885		$ 218,018