XML 60 R48.htm IDEA: XBRL DOCUMENT
v3.23.3

Note 8 - Investments, Including Investments Accounted for Using the Equity Method (Details Textual) - USD ($) |  |  |  |  | 1 Months Ended | 3 Months Ended | 4 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
May 01, 2023 | Jan. 25, 2022 | Sep. 14, 2021 | May 31, 2018 | Jul. 31, 2023 | Oct. 31, 2020 | Jan. 31, 2018 | Sep. 30, 2023 | Sep. 30, 2022 | Mar. 31, 2022 | Nov. 30, 2020 | Sep. 30, 2023 | Sep. 30, 2022 | Dec. 31, 2022 | May 31, 2023
Debt Securities, Trading |  |  |  |  |  |  |  | $ 53,549,016 |  |  |  | $ 53,549,016 |  | $ 33,520,401 |
Class of Warrant or Right, Exercise Price of Warrants or Rights (in dollars per share) |  |  |  |  |  |  |  | $ 9.95 |  |  |  | $ 9.95 |  | $ 9.95 |
Payments to Acquire Equity Method Investments |  |  |  |  |  |  |  |  |  |  |  | $ 3,000,000 | $ 45,000,000 |  |
Deconsolidation, Gain (Loss), Amount |  |  |  |  |  |  |  | $ 0 | $ 0 |  |  | 0 | $ 24,977,740 |  |
Deconsolidation, Gain (Loss), Recognized, Amount |  |  |  |  |  |  |  |  |  |  |  | $ 0 |  | $ 10,010,090 |
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 |  |  |  |  |  |  |  |  |  |  |  |
Sky Harbour Group Corporation Class A Common Stock [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Equity Method Investment, Ownership Percentage |  |  |  |  |  |  |  | 22.90% |  | 22.90% |  | 22.90% |  |  |
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 |  |  |  |  |  | 13,118,474 |  | 13,118,474 |  | 13,118,474 |  |  |
Deconsolidation, Gain (Loss), Amount |  |  |  |  |  |  |  |  |  | $ 24,977,740 |  |  |  |  |
Deconsolidation, Gain (Loss), Recognized, Amount |  |  |  |  |  |  |  |  |  | 10,000,000 |  |  |  |  |
Deconsolidation, Gain (Loss), Assets and Liabilities |  |  |  |  |  |  |  |  |  | $ 15,000,000 |  |  |  |  |
Equity Method Investment, Quoted Market Value |  |  |  |  |  |  |  | $ 58,900,000 |  |  |  | $ 58,900,000 |  |  |
Equity Method Investments, Price Per Share (in dollars per share) |  |  |  |  |  |  |  | $ 7.77 |  |  |  | $ 7.77 |  |  |
Yellowstone Acquisition Company [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Proceeds from Issuance Initial Public Offering |  |  |  |  |  | $ 125,000,000 |  |  |  |  |  |  |  |  |
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 |  |  |  |  |  |  |  |  |
Sale of Unit, Price Per Unit (in dollars per share) |  |  |  |  |  | $ 10 |  |  |  |  |  |  |  |  |
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 |  |  |  |
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 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain | $ 4,600,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |
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 |  |  |  |  |  |  |  |  |  |  |  |  |  |
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 |  |  |  |  |  |  |  |  |  |  |  |  |
Breezeway Homes Inc. [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Preferred Stock, Dividend Rate, Per-Dollar-Amount (in dollars per share) |  |  |  |  |  |  | $ 2,665 |  |  |  |  |  |  |  |
Preferred Stock [Member] | Breezeway Homes Inc. [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Conversion, Converted Instrument, Shares Issued (in shares) |  |  |  |  |  |  | 31,227 |  |  |  |  |  |  |  |
Voting Common Stock of Privately Held Company CB&T Holding Corporation [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Long-term Investments |  |  |  | $ 19,058,485 |  |  |  |  |  |  |  |  |  |  |
Cost Method Investment, Ownership Percentage |  |  |  | 15.60% |  |  |  |  |  |  |  |  |  |  |
Equity Investments [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Other than Temporary Impairment Losses, Investments |  |  |  |  |  |  |  |  |  |  |  | $ 0 |  |  |
Class B Common Stock of Yellowstone Acquisition Company [Member] | BOC Yellowstone LLC [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Payments to Acquire Investments, Total |  |  |  |  |  |  |  |  |  |  | $ 7,800,000 |  |  |  |
Investment Owned, Balance, Shares (in shares) |  |  |  |  |  |  |  |  |  |  | 3,399,724 |  |  |  |
US Treasury Securities [Member] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt Securities, Trading |  |  |  |  |  |  |  | $ 26,920,747 |  |  |  | $ 26,920,747 |  |  |

X
- Definition Represents the maximum value of the backstop agreed to be provided to the acquiree in a business combination. + References No definition available. + Details
Name: | boc_BusinessAcquisitionBackstopAgreedToBeProvidedToAcquireeMaximumValue
Namespace Prefix: | boc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents the price per share of the backstop agreed to be provided to the acquiree in a business combination. + References No definition available. + Details
Name: | boc_BusinessAcquisitionBackstopAgreedToBeProvidedToAcquireePricePerShare
Namespace Prefix: | boc_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the cost method of accounting. + References No definition available. + Details
Name: | boc_CostMethodInvestmentOwnershipPercentage
Namespace Prefix: | boc_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the assets and liabilities related to deconsolidation. + References No definition available. + Details
Name: | boc_DeconsolidationGainLossAssetsAndLiabilities
Namespace Prefix: | boc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Represents the recognized gain (loss) related to deconsolidation. + References No definition available. + Details
Name: | boc_DeconsolidationGainLossRecognizedAmount
Namespace Prefix: | boc_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The price per share of equity investment method equity interest. + References No definition available. + Details
Name: | boc_EquityMethodInvestmentPricePerShare
Namespace Prefix: | boc_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of shares. + References No definition available. + Details
Name: | boc_EquityMethodInvestmentShares
Namespace Prefix: | boc_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of shares of equity method investment converted from other equity during period. + References No definition available. + Details
Name: | boc_EquityMethodInvestmentSharesConvertedFromOtherEquity
Namespace Prefix: | boc_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition This item represents the carrying amount, per share, on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized. + References No definition available. + Details
Name: | boc_EquityMethodInvestmentsPricePerShare
Namespace Prefix: | boc_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Per unit amount received by subsidiary or equity investee for each unit issued or sold in the stock transaction. + References No definition available. + Details
Name: | boc_SaleOfUnitPricePerUnit
Namespace Prefix: | boc_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of units issued during the period + References No definition available. + Details
Name: | boc_UnitsIssuedDuringPeriodNumber
Namespace Prefix: | boc_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of common stock shares in each unit issued during the period. + References No definition available. + Details
Name: | boc_UnitsIssuedDuringPeriodNumberOfCommonStockShares
Namespace Prefix: | boc_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The number of warrants per units issued during the period. + References No definition available. + Details
Name: | boc_UnitsIssuedDuringPeriodNumberOfWarrants
Namespace Prefix: | boc_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition The price per unit of the units issued during the period. + References No definition available. + Details
Name: | boc_UnitsIssuedDuringPeriodPricePerUnit
Namespace Prefix: | boc_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares of equity interests issued or issuable to acquire entity. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 805 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(4) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479581/805-30-50-1 + Details
Name: | us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of voting equity interests acquired at the acquisition date in the business combination. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479328/805-10-50-2 + Details
Name: | us-gaap_BusinessAcquisitionPercentageOfVotingInterestsAcquired
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 30 -Paragraph 8 -SubTopic 30 -Topic 805 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479637/805-30-30-8 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b) -SubTopic 30 -Topic 805 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479581/805-30-50-1 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 30 -Paragraph 7 -SubTopic 30 -Topic 805 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479637/805-30-30-7 + Details
Name: | us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Percentage of equity in the acquiree held by the acquirer immediately before the acquisition date in a business combination. + References No definition available. + Details
Name: | us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireePercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition In a business combination achieved in stages, this element represents the amount of gain recognized by the entity as a result of remeasuring to fair value the equity interest in the acquiree it held before the business combination. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 805 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (g)(2) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479328/805-10-50-2 + Details
Name: | us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeRemeasurementGain
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Exercise price per share or per unit of warrants or rights outstanding. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481112/505-10-50-3 + Details
Name: | us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of securities into which each warrant or right may be converted. For example, but not limited to, each warrant may be converted into two shares. + References No definition available. + Details
Name: | us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByEachWarrantOrRight
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481112/505-10-50-3 + Details
Name: | us-gaap_ClassOfWarrantOrRightNumberOfSecuritiesCalledByWarrantsOrRights
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482913/230-10-50-3 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 5 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482913/230-10-50-5 + Details
Name: | us-gaap_DebtConversionConvertedInstrumentSharesIssued1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of gain (loss) from deconsolidation of subsidiary and derecognition of group of assets constituting transfer of business or nonprofit activity, excluding conveyance of oil and gas mineral rights and transfer of good or service in contract with customer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 810 -SubTopic 10 -Section 50 -Paragraph 1B -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481203/810-10-50-1B + Details
Name: | us-gaap_DeconsolidationGainOrLossAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481687/323-10-50-3 + Details
Name: | us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition This item represents the aggregate value of each identified investment accounted for under the equity method of accounting based on the quoted market price for those investments in common stock for which a quoted market price is available. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 323 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481687/323-10-50-3 + Details
Name: | us-gaap_EquityMethodInvestmentQuotedMarketValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The amount by which the fair value of an investment is less than the amortized cost basis or carrying amount of that investment at the balance sheet date and the decline in fair value is deemed to be other than temporary, before considering whether or not such amount is recognized in earnings or other comprehensive income. + References Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 8A -Publisher FASB -URI https://asc.fasb.org//1943274/2147481830/320-10-45-8A + Details
Name: | us-gaap_ImpairmentOfInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Number of shares of investment owned. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-6 Reference 2: http://www.xbrl.org/2003/role/exampleRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 55 -Paragraph 1 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480493/946-210-55-1 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 210 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (a)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480524/946-210-50-1 Reference 4: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-12(Column B)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-1 Reference 5: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 3 -Subparagraph (SX 210.12-12B(Column B)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-3 Reference 6: http://www.xbrl.org/2003/role/disclosureRef -Topic 946 -SubTopic 320 -Name Accounting Standards Codification -Section S99 -Paragraph 6 -Subparagraph (SX 210.12-14(Column B)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480032/946-320-S99-6 + Details
Name: | us-gaap_InvestmentOwnedBalanceShares
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 805 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (b)(1) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479581/805-30-50-1 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-13 + Details
Name: | us-gaap_PaymentsToAcquireBusinessesGross
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-13 + Details
Name: | us-gaap_PaymentsToAcquireEquityMethodInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow associated with the purchase of all investments (debt, security, other) during the period. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 13 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-13 + Details
Name: | us-gaap_PaymentsToAcquireInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The cash outflow for securities or other assets acquired, which qualify for treatment as an investing activity and are to be liquidated, if necessary, beyond the current operating cycle. Includes cash flows from securities classified as trading securities that were acquired for reasons other than sale in the long-term. + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 230 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 13 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-13 + Details
Name: | us-gaap_PaymentsToAcquireLongtermInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition The amount per share used to calculated dividend payments on preferred stock. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 505 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 13 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481112/505-10-50-13 + Details
Name: | us-gaap_PreferredStockDividendRatePerDollarAmount
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition The cash inflow associated with the amount received from entity's first offering of stock to the public. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 14 -Subparagraph (a) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-14 + Details
Name: | us-gaap_ProceedsFromIssuanceInitialPublicOffering
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Amount of investment in debt security measured at fair value with change in fair value recognized in net income (trading). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481830/320-10-45-1 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(2)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1 Reference 3: http://www.xbrl.org/2003/role/exampleRef -Topic 210 -SubTopic 10 -Name Accounting Standards Codification -Section 45 -Paragraph 1 -Subparagraph (f) -Publisher FASB -URI https://asc.fasb.org//1943274/2147483467/210-10-45-1 + Details
Name: | us-gaap_TradingSecuritiesDebt
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=boc_YellowstoneAcquisitionCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=boc_SkyHarbourGroupCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=boc_SkyHarbourGroupCorporationClassACommonStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=boc_YellowstoneAcquisitionCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_SubsidiarySaleOfStockAxis=us-gaap_IPOMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementClassOfStockAxis=us-gaap_CommonClassAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=boc_YellowstoneAcquisitionCompanyWarrantsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=boc_BOCYellowstoneLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ClassOfWarrantOrRightAxis=boc_NonredeemablePrivatePlacementWarrantsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=boc_The24thStreetAssetManagementLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=boc_BostonOmahaAssetManagementLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ContingentConsiderationByTypeAxis=boc_HoldbackCashConsiderationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=boc_MyBundleTvIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_BusinessAcquisitionAxis=boc_BusinessCombinationAgreementWithSHGMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_CounterpartyNameAxis=boc_BreezewayHomesIncMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_StatementEquityComponentsAxis=us-gaap_PreferredStockMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=boc_VotingCommonStockOfPrivatelyHeldCompanyCBTHoldingCorporationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=boc_EquityInvestmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_InvestmentTypeAxis=boc_ClassBCommonStockOfYellowstoneAcquisitionCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |