Note 5 - Receivables, Accounts Payable and Accrued Liabilities (Details) - Summary of Accounts Payable (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Summary of Accounts Payable [Abstract]
Accounts payable - joint venture	$ 2,947bpz_AccountsPayableJointVenturePartner
Other accounts payable	1,433us-gaap_AccountsPayableOtherCurrent	3,127us-gaap_AccountsPayableOtherCurrent
Accounts payable	$ 4,380us-gaap_AccountsPayableCurrent	$ 3,127us-gaap_AccountsPayableCurrent

Carrying value as of the balance sheet date of obligations incurred and payable, which are not elsewhere specified in the taxonomy. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19

-Subparagraph a

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Current Liabilities

-URI http://asc.fasb.org/extlink&oid=6509677

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section 45

-Paragraph 8

-URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6935-107765

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(a))

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

Name:	us-gaap_AccountsPayableOtherCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant