2.4.0.8070 - Disclosure - Note 13 - Fair Value Measurements and Disclosures (Details)truefalseIn Thousands, unless otherwise specifiedfalse1false USDfalsefalse$c0_AsOf30Jun2013http://www.sec.gov/CIK0001023734instant2013-06-30T00:00:000001-01-01T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$2false USDfalsefalse$c1_AsOf31Dec2012http://www.sec.gov/CIK0001023734instant2012-12-31T00:00:000001-01-01T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$3false USDfalsefalse$c75_AsOf31Jul2011http://www.sec.gov/CIK0001023734instant2011-07-31T00:00:000001-01-01T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$4false USDfalsefalse$c78_AsOf31Jan2011http://www.sec.gov/CIK0001023734instant2011-01-31T00:00:000001-01-01T00:00:00usdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$5false USDtruefalse$c33_AsOf30Jun2013_FortyMillionDollarSecuredDebtFacilityMemberhttp://www.sec.gov/CIK0001023734instant2013-06-30T00:00:000001-01-01T00:00:00falsefalse$40 Million Secured Debt Facility [Member]us-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldibpz_FortyMillionDollarSecuredDebtFacilityMemberus-gaap_DebtInstrumentAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$6false USDtruefalse$c124_AsOf31May2013_FortyMillionDollarSecuredDebtFacilityMemberhttp://www.sec.gov/CIK0001023734instant2013-05-31T00:00:000001-01-01T00:00:00falsefalse$40 Million Secured Debt Facility [Member]us-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldibpz_FortyMillionDollarSecuredDebtFacilityMemberus-gaap_DebtInstrumentAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$7false USDtruefalse$c79_AsOf31Dec2012_FortyMillionDollarSecuredDebtFacilityMemberhttp://www.sec.gov/CIK0001023734instant2012-12-31T00:00:000001-01-01T00:00:00falsefalse$40 Million Secured Debt Facility [Member]us-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldibpz_FortyMillionDollarSecuredDebtFacilityMemberus-gaap_DebtInstrumentAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$8false USDtruefalse$c36_AsOf31Jan2011_FortyMillionDollarSecuredDebtFacilityMemberhttp://www.sec.gov/CIK0001023734instant2011-01-31T00:00:000001-01-01T00:00:00falsefalse$40 Million Secured Debt Facility [Member]us-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldibpz_FortyMillionDollarSecuredDebtFacilityMemberus-gaap_DebtInstrumentAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$9false USDtruefalse$c32_AsOf30Jun2013_SeventyFiveMillionDollarSecuredDebtFacilityMemberhttp://www.sec.gov/CIK0001023734instant2013-06-30T00:00:000001-01-01T00:00:00falsefalse$75 Million Secured Debt Facility [Member]us-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldibpz_SeventyFiveMillionDollarSecuredDebtFacilityMemberus-gaap_DebtInstrumentAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$10false USDtruefalse$c76_AsOf31Dec2012_SeventyFiveMillionDollarSecuredDebtFacilityMemberhttp://www.sec.gov/CIK0001023734instant2012-12-31T00:00:000001-01-01T00:00:00falsefalse$75 Million Secured Debt Facility [Member]us-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldibpz_SeventyFiveMillionDollarSecuredDebtFacilityMemberus-gaap_DebtInstrumentAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$11false USDtruefalse$c37_AsOf31Jul2011_SeventyFiveMillionDollarSecuredDebtFacilityMemberhttp://www.sec.gov/CIK0001023734instant2011-07-31T00:00:000001-01-01T00:00:00falsefalse$75 Million Secured Debt Facility [Member]us-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldibpz_SeventyFiveMillionDollarSecuredDebtFacilityMemberus-gaap_DebtInstrumentAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$12false USDtruefalse$c178_AsOf30Jun2013_TwoThousandFifteenConvertibleNotesMemberhttp://www.sec.gov/CIK0001023734instant2013-06-30T00:00:000001-01-01T00:00:00falsefalse2015 Convertible Notes [Member]us-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldibpz_TwoThousandFifteenConvertibleNotesMemberus-gaap_DebtInstrumentAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$13false USDtruefalse$c179_AsOf31Dec2012_TwoThousandFifteenConvertibleNotesMemberhttp://www.sec.gov/CIK0001023734instant2012-12-31T00:00:000001-01-01T00:00:00falsefalse2015 Convertible Notes [Member]us-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldibpz_TwoThousandFifteenConvertibleNotesMemberus-gaap_DebtInstrumentAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$14false USDtruefalse$c177_AsOf31Mar2010_TwoThousandFifteenConvertibleNotesMemberhttp://www.sec.gov/CIK0001023734instant2010-03-31T00:00:000001-01-01T00:00:00falsefalse2015 Convertible Notes [Member]us-gaap_DebtInstrumentAxisxbrldihttp://xbrl.org/2006/xbrldibpz_TwoThousandFifteenConvertibleNotesMemberus-gaap_DebtInstrumentAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$15false USDtruefalse$c176_AsOf30Jun2013_USTreasuryBillSecuritiesMemberhttp://www.sec.gov/CIK0001023734instant2013-06-30T00:00:000001-01-01T00:00:00falsefalseUS Treasury Bill Securities [Member]us-gaap_InvestmentTypeAxisxbrldihttp://xbrl.org/2006/xbrldius-gaap_USTreasuryBillSecuritiesMemberus-gaap_InvestmentTypeAxisexplicitMemberusdStandardhttp://www.xbrl.org/2003/iso4217USDiso42170USDUSD$1true 3bpz_Note13FairValueMeasurementsandDisclosuresDetailsLineItemsbpz_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalse8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalse12falsefalsefalse00falsefalsefalse13falsefalsefalse00falsefalsefalse14falsefalsefalse00falsefalsefalse15falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Note 13 - Fair Value Measurements and Disclosures (Details) [Line Items]2false 4us-gaap_DebtInstrumentFaceAmountus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsetruefalseperiodEndLabel1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalse3truefalsefalse7500000075000USD$falsetruefalse4truefalsefalse4000000040000USD$falsetruefalse5truefalsefalse4000000040000USD$falsetruefalse6truefalsefalse2550000025500USD$falsetruefalse7truefalsefalse4000000040000USD$falsetruefalse8truefalsefalse4000000040000USD$falsetruefalse9truefalsefalse7500000075000USD$falsetruefalse10truefalsefalse7500000075000USD$falsetruefalse11truefalsefalse7500000075000USD$falsetruefalse12falsefalsefalse00falsefalsefalse13falsefalsefalse00falsefalsefalse14truefalsefalse170900000170900USD$falsetruefalse15falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryFace (par) amount of debt instrument at time of issuance.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400 false2Debt Instrument, Face Amount3false 4us-gaap_HeldToMaturitySecuritiesFairValueus-gaap_truedebitinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse10000001000[1]falsefalsefalse2truefalsefalse00falsefalsefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalse8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalse12falsefalsefalse00falsefalsefalse13falsefalsefalse00falsefalsefalse14falsefalsefalse00falsefalsefalse15truefalsefalse10000001000falsefalsefalsexbrli:monetaryItemTypemonetaryFair value of investments in debt securities classified as held-to-maturity.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (f) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 false2Held-to-maturity Securities, Fair Value4false 4us-gaap_ConvertibleDebtFairValueDisclosuresus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseverboseLabel1truefalsefalse138460000138460[2]USD$falsetruefalse2truefalsefalse147861000147861[2]USD$falsetruefalse3falsefalsefalse00falsefalsefalse4falsefalsefalse00falsefalsefalse5falsefalsefalse00falsefalsefalse6falsefalsefalse00falsefalsefalse7falsefalsefalse00falsefalsefalse8falsefalsefalse00falsefalsefalse9falsefalsefalse00falsefalsefalse10falsefalsefalse00falsefalsefalse11falsefalsefalse00falsefalsefalse12truefalsefalse138500000138500USD$falsetruefalse13truefalsefalse147900000147900USD$falsetruefalse14falsefalsefalse00falsefalsefalse15falsefalsefalse00falsefalsefalsexbrli:monetaryItemTypemonetaryFair value portion of borrowing which can be exchanged for a specified number of another security at the option of the issuer or the holder, for example, but not limited to, the entity's common stock.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Convertible Security -URI http://asc.fasb.org/extlink&oid=6509036 false2Convertible Debt, Fair Value Disclosures1The Company estimated the fair value of the U.S. Treasury bill to be approximately $1.0 million at June 30, 2013, based on observed market prices for the same or similar types of debt issues. The fair value of the U.S. Treasury bill is considered to be a Level 2 measurement on the fair value hierarchy.2The Company estimated the fair value of the $170.9 million 2015 Convertible Notes to be approximately $138.5 million and $147.9 million at June 30, 2013 and December 31, 2012, respectively, based on observed market prices for the same or similar types of debt issues. The fair value of the $170.9 million 2015 Convertible Notes is considered to be a Level 1 measurement on the fair value hierarchy.falseNote 13 - Fair Value Measurements and Disclosures (Details) (USD $)ThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://bpzenergy.com/role/Note13FairValueMeasurementsandDisclosuresDetails154