Note 5 - Receivables, Accounts Payable and Accrued Liabilities (Details) - Value-added Tax Receivable (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Value-added Tax Receivable [Abstract]
Value-added tax receivable as of the beginning of the period	$ 12,262us-gaap_ValueAddedTaxReceivable	$ 21,784us-gaap_ValueAddedTaxReceivable
IGV accrued related to expenditures during period	13,943	12,722
IGV reduced related to sale of oil during period	(21,712)	(22,244)
Value-added tax receivable as of the end of the period	4,493us-gaap_ValueAddedTaxReceivable	12,262us-gaap_ValueAddedTaxReceivable
Current portion of value-added tax receivable as of the end of the period	2,343us-gaap_ValueAddedTaxReceivableCurrent	10,490us-gaap_ValueAddedTaxReceivableCurrent
Long-term portion of value-added tax receivable as of the end of the period	$ 2,150	$ 1,772

Accrual of value-added taxes for purchases during the period.

No definition available.

Name:	bpz_ValueAddedTaxAccruedRelatedToExpendituresDuringPeriod
Namespace Prefix:	bpz_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	bpz_ValueAddedTaxReceivableAbstract
Namespace Prefix:	bpz_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Reduction in value-added taxes due to the sale of oil during the period.

+ References

No definition available.

+ Details

Name:	bpz_ValueAddedTaxReducedRelatedToSaleOfOilDuringPeriod
Namespace Prefix:	bpz_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Carrying amount as of the balance sheet date of value added taxes due either from customers arising from sales on credit terms, or as previously overpaid to tax authorities.

+ References

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)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 8

-Article 5

+ Details

Name:	us-gaap_ValueAddedTaxReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of value added taxes due either from customers arising from sales on credit terms, or as previously overpaid to tax authorities. For classified balance sheets, represents the current amount receivable, that is amounts expected to be collected within one year or the normal operating cycle, if longer.

+ References

+ Details

Name:	us-gaap_ValueAddedTaxReceivableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount due after one year of the balance sheet date (or one operating cycle), if longer of value added taxes due either from customers arising from sales on credit terms, or as previously overpaid to tax authorities.

+ References

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 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 8

-Article 5

+ Details

Name:	us-gaap_ValueAddedTaxReceivableNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant