2.4.0.8073 - Disclosure - Note 13 - Fair Value Measurements and Disclosures (Details) - Fair Value of Company’s Fixed Rate DebttruefalseIn 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$1true 1bpz_FairValueOfCompanySFixedRateDebtAbstractbpz_falsenadurationfalsefalsefalsefalsefalsefalsefalsefalse1falsefalsefalse00falsefalsefalse2falsefalsefalse00falsefalsefalsexbrli:stringItemTypestringfalse0Fair Value of Company’s Fixed Rate Debt [Abstract]2false 2us-gaap_ConvertibleDebtus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalselabel1truefalsefalse157132000157132USD$falsetruefalse2truefalsefalse153479000153479USD$falsetruefalsexbrli:monetaryItemTypemonetaryIncluding the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company.Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16(a)(2)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 19, 20, 22 -Article 5 false2$170.9 million Convertible Notes, 6.5%, due March 2015, net of discount of ($13.8) million at June 30, 2013 and ($17.4) million at December 31, 20123false 2us-gaap_ConvertibleDebtFairValueDisclosuresus-gaap_truecreditinstantfalsefalsefalsefalsefalsefalsefalsefalseterseLabel1truefalsefalse138460000138460[1]USD$falsetruefalse2truefalsefalse147861000147861[1]USD$falsetruefalsexbrli: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 false2$170.9 million Convertible Notes, 6.5%, due March 2015, net of discount of ($13.8) million at June 30, 2013 and ($17.4) million at December 31, 20121The 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) - Fair Value of Company’s Fixed Rate Debt (USD $)ThousandsUnKnownUnKnownUnKnowntruefalsefalseSheethttp://bpzenergy.com/role/FairValueofCompanysFixedRateDebtTable23