Note 7 - Investments, Including Investments Accounted for Using the Equity Method (Details Textual) - USD ($)							1 Months Ended			2 Months Ended	3 Months Ended		4 Months Ended	12 Months Ended
	Dec. 20, 2024	Oct. 25, 2024	Nov. 02, 2023	May 01, 2023	Jan. 25, 2022	Sep. 14, 2021	Jul. 31, 2023	Oct. 31, 2020	May 31, 2018	Dec. 20, 2024	Dec. 31, 2024	Dec. 31, 2023	Nov. 30, 2020	Dec. 31, 2025	Dec. 31, 2024	Nov. 29, 2023	May 31, 2023	Apr. 25, 2022
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)											$ 9.95	$ 9.95		$ 0	$ 9.95
Payments to Acquire Equity Method Investments														$ (0)	$ 21,000
Common Stock, Par or Stated Value Per Share (in dollars per share)																		$ 0.001
Common Class A [Member]
Common Stock, Par or Stated Value Per Share (in dollars per share)											$ 0.001			$ 0.001	$ 0.001
CB&T Holding Corporation [Member]
Equity Method Investment, Ownership Percentage									15.60%
Yellowstone Acquisition Company [Member]
Equity Method Investment, Ownership Percentage													20.00%
Sky Harbour Group Corporation [Member]
Payments to Acquire Equity Method Investments						$ 55,000,000
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic											$ 5,100,000
Sky Harbour Group Corporation Class A Common Stock [Member]
Equity Method Investment, Ownership Percentage											16.40%			15.30%	16.40%
Payments to Acquire Equity Method Investments					$ 45,000,000
Equity Method Investment, Shares, Converted from Other Equity (in shares)					5,500,000
Equity Method Investment, Price Per Share (in dollars per share)					$ 10
Equity Method Investment, Shares (in shares)					4,500,000						12,401,589			11,671,494	12,401,589
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic												$ 2,200,000
Equity Method Investment, Quoted Market Value											$ 148,000,000			$ 105,000,000	$ 148,000,000
Yellowstone Acquisition Company [Member] | IPO [Member]
Units Issued During Period, Number (in shares)								13,598,898
Units Issued During Period, Price Per Unit (in dollars per share)								$ 10
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)								$ 11.5
Yellowstone Acquisition Company [Member] | IPO [Member] | Common Class A [Member]
Units Issued During Period, Number of Common Stock, Shares (in shares)								1
Yellowstone Acquisition Company Warrants [Member] | IPO [Member]
Units Issued During Period, Number of Warrants (in shares)								0.5
BOC Yellowstone LLC [Member] | Non-redeemable Private Placement Warrants [Member]
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share)													$ 11.5
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)													7,719,779
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right (in shares)													1
BOC Yellowstone LLC [Member] | Class B Common Stock of Yellowstone Acquisition Company [Member]
Payments to Acquire Investments, Total													$ 7,800,000
Investment Owned, Balance, Shares (in shares)													3,399,724
Sky Harbour Group Corporation [Member] | Private Placement [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)			1,141,600
Stock Issued During Period, Shares, New Issues (in shares)	3,955,790	3,955,790	6,586,154
Common Stock, Par or Stated Value Per Share (in dollars per share)			$ 0.0001
Proceeds from Issuance or Sale of Equity			$ 42,810,000							$ 75,200,000
Stock Issued During Period, Value, New Issues	$ 37,600,000	$ 37,600,000
Shares Issued, Price Per Share (in dollars per share)	$ 9.5									$ 9.5
Sky Harbour Group Corporation [Member] | Additional PIPE Offering [Member]
Class of Warrant or Right, Number of Securities Called by Warrants or Rights (in shares)																400,000
Common Stock, Par or Stated Value Per Share (in dollars per share)																$ 0.0001
Proceeds from Issuance or Sale of Equity			$ 57,810,000
Equity Offering, Maximum Shares (in shares)																2,307,692
Equity Offering, Maximum Amount																$ 15,000,000
The 24th Street Asset Management, LLC [Member] | Boston Omaha Asset Management, LLC [Member]
Business Acquisition, Percentage of Voting Interests Acquired				100.00%
Business Combination, Consideration Transferred				$ 5,016,494
Business Combination, Step Acquisition, Equity Interest in Acquiree, Percentage																	48.00%
Payments to Acquire Businesses, Gross				$ 2,759,072
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares (in shares)				45,644
The 24th Street Asset Management, LLC [Member] | Boston Omaha Asset Management, LLC [Member] | Holdback Cash Consideration [Member]
Payments to Acquire Businesses, Gross				$ 1,254,102
CB&T Holding Corporation [Member]
Payments to Acquire Businesses, Gross									$ 19,058,485
My Bundle TV Inc. [Member]
Payments to Acquire Businesses, Gross							$ 3,000,000
Business Combination Agreement with SHG [Member]
Payments to Acquire Businesses, Gross						55,000,000
Business Acquisition, Backstop Agreed to Be Provided to Acquiree, Maximum Value						$ 45,000,000
Business Acquisition, Backstop Agreed to Be Provided to Acquiree, Price Per Share (in dollars per share)						$ 10