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Amount recognized for assets, including goodwill, in excess of (less than) the aggregate liabilities assumed.

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Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Note 6 - Business Acquisitions (Details Textual) - USD ($)					3 Months Ended		9 Months Ended
	Aug. 30, 2019	Aug. 31, 2018	Aug. 22, 2018	Jul. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Payments to Acquire Businesses, Net of Cash Acquired, Total							$ 6,516,751	$ 135,023,950
Goodwill, Ending Balance					$ 105,757,891		$ 105,757,891		$ 98,685,795
Minimum [Member]
Property, Plant and Equipment, Useful Life							2 years
Finite-Lived Intangible Asset, Useful Life							2 years
Maximum [Member]
Property, Plant and Equipment, Useful Life							15 years
Finite-Lived Intangible Asset, Useful Life							50 years
Image Outdoor Advertising, LLC [Member]
Payments to Acquire Businesses, Net of Cash Acquired, Total	$ 6,915,501
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares	34,673
Business Combination, Amount Held Back and Disbursed	$ 398,750
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Total	1,565,065
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill, Total	3,145,000
Goodwill, Ending Balance	3,045,538
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other	$ 129,999
Tammy Lynn Outdoor, LLC [Member]
Payments to Acquire Businesses, Net of Cash Acquired, Total				$ 14,763,261
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual						$ 340,006
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual								(54,969)
Business Combination, Acquisition Related Costs						113,679		113,679
Tammy Lynn Outdoor, LLC [Member] \| Common Class A [Member]
Stock Issued During Period, Shares, Acquisitions				85,170
Key Outdoor, Inc [Member]
Business Combination, Amount Held Back and Disbursed			$ 1,900,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Total					6,927,808		$ 6,927,808		9,603,838
Goodwill, Ending Balance					21,257,030		21,257,030		19,499,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual						555,992
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual								(6,756)
Business Combination, Acquisition Related Costs						121,469		121,469
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net, Total			38,000,000		38,233,894		38,233,894		38,233,894
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred			233,894
Business Combination, Amount Held Back as Required Consent Holdback			329,467
Payments to Acquire Businesses, Gross			$ 36,004,427
Payments on Short-term Payables for Business Acquisitions							1,964,990
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Amortization					335,797		335,797
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Depreciation					(193,269)		(193,269)
Waitt Outdoor, LLC [Member]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment, Total					16,220,375		16,220,375		19,723,904
Goodwill, Ending Balance					48,650,475		48,650,475		46,381,946
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other					1,316,000		1,316,000		1,316,000
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual						1,117,509
Business Combination, Pro Forma Information, Earnings or Loss of Acquiree since Acquisition Date, Actual								32,312
Business Combination, Acquisition Related Costs						$ 140,165		$ 140,165
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net, Total		$ 82,000,000			84,031,262		84,031,262		$ 84,031,262
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Consideration Transferred		2,031,262
Payments to Acquire Businesses, Gross		84,031,262
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Amortization					459,369		459,369
Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Depreciation					$ (253,033)		$ (253,033)
Other Restricted Assets, Noncurrent		$ 4,102,500