2.4.0.8040012 - Disclosure - Significant Accounting Policies - Cash (Details)truefalsefalse1false USDfalsefalseFROM_Jan01_2013_TO_Jun30_2013http://www.sec.gov/CIK0001275477duration2013-01-01T00:00:002013-06-30T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170$2false USDfalsefalse$AS_OF_Dec31_2012http://www.sec.gov/CIK0001275477instant2012-12-31T00:00:000001-01-01T00:00:00USDStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 1bmnm_SignificantAccountingPoliciesAbstractbmnm_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Significant Accounting Policies [Abstract]2false 2us-gaap_CashUninsuredAmountCommentaryus-gaap_truenadurationfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1falsefalsefalse00The Company maintains cash balances at three banks, and, at times, balances may exceed federally insured limits. The Company has not experienced any losses related to these balances. All non-interest bearing cash balances were fully insured at December 31, 2012 due to a temporary federal program in effect from December 31, 2010 through December 31, 2012. Under the program, there was no limit to the amount of insurance for eligible accounts. Beginning January 1, 2013, insurance reverted to $250,000 per depositor at each financial institution. At June 30, 2013, the Company’s cash deposits exceeded federally insured limits by approximately $7.3 million. Restricted cash balances are uninsured, but are held in separate customer accounts that are segregated from the general funds of the counterparty. The Company believes that it is not exposed to any significant credit risk on cash and cash equivalents or restricted cash balancesfalsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringInformation about cash that is uninsured. May discuss factors mitigating risk of loss due to failure of a financial institution in which the cash is deposited, or an assertion that risk of loss is considered very low.No definition available.false0Commentary - Cash and Cash Equivalents Balances That Are Insured by the FDIC3false 2bmnm_RepurchaseAgreementMarginbmnm_falsedebitinstantfalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse66290006629000USD$falsetruefalse2truefalsefalse614000614000USD$falsetruefalsexbrli:monetaryItemTypemonetaryNo authoritative reference available.No definition available.false2Repurchase Agreement Margin4false 2us-gaap_MarginDepositAssetsus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse26820002682000falsefalsefalse2truefalsefalse227000227000falsefalsefalsexbrli:monetaryItemTypemonetaryThe amount of cash or securities placed with a broker or counterparty as security for a trading or derivatives securities position which was partially obtained with funds provided by the broker dealer.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.8,17) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 false2Cash Held by Broker as Margin on Eurodollar Futures Contracts5false 2us-gaap_CashUninsuredAmountus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalse1truefalsefalse73000007300000USD$falsetruefalse2falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryThe amount of cash as of the balance sheet date that is not insured by the Federal Deposit Insurance Corporation.No definition available.false2CashUninsuredAmountfalseSignificant Accounting Policies - Cash (Details) (USD $)NoRoundingUnKnownUnKnownUnKnowntruefalsefalseSheethttp://www.biminicapital.com/role/SignificantAccountingPoliciesCashDetails25