Accrued director compensation.

No definition available.

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- Definition

Number of additional units that can be purchased by the underwriters to cover over-allotments.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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- Definition

Incurred director compensation.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Period of time from the date of the final prospectus relating to the Initial Public Offering for underwriters to purchase additional Units to cover over-allotments, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Percentage of cash underwriting discount.

+ References

No definition available.

+ Details

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Data Type:	dtr:percentItemType
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- Definition

Service fees.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(20))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480566/210-10-S99-1

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of fee income including, but not limited to, managerial assistance, servicing of investment, and origination and commitment fees.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(1)(c))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of expense for service provided by entity's director.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(14))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.6-07(2)(b))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479134/946-220-S99-1

Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 946
-SubTopic 220
-Name Accounting Standards Codification
-Section 45
-Paragraph 3
-Subparagraph (l)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479105/946-220-45-3

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The cash inflow associated with the amount received from entity's first offering of stock to the public.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Section 45
-Paragraph 14
-Subparagraph (a)
-SubTopic 10
-Topic 230
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482740/230-10-45-14

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

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Data Type:	na
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Period Type:

- Details

Name:	us-gaap_SubsidiarySaleOfStockAxis=us-gaap_IPOMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	bpac_TypeOfUnderwritingAxis=bpac_CashUnderwritingDiscountMember
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Commitments and Contingencies (Details) - USD ($)			3 Months Ended	6 Months Ended
Commitments and Contingencies (Details) - USD ($)	Nov. 13, 2025	Nov. 11, 2025	Jun. 30, 2026	Jun. 30, 2026	Dec. 31, 2025
Commitments and Contingencies (Details) [Line Items]
Monthly fee		$ 3,000
Service fees			$ 9,000	$ 18,000
Accrued liabilities			6,000	6,000	$ 0
Incurred director compensation			22,500	45,000
Accrued director compensation			$ 15,000	$ 0
Option for underwriters to purchase additional units, term				45 days
Number of additional units that can be purchased by the underwriters to cover over-allotments. (in Shares)			750,000	750,000
Percentage of cash underwriting discount				1.50%
Director [Member]
Commitments and Contingencies (Details) [Line Items]
Director fees				$ 7,500
IPO [Member]
Commitments and Contingencies (Details) [Line Items]
Gross proceeds from proposed public offering	$ 57,500,000			$ 57,500,000
Cash Underwriting Discount [Member]
Commitments and Contingencies (Details) [Line Items]
Percentage of cash underwriting discount				2.00%
Gross proceeds from proposed public offering				$ 862,500
Cash Underwriting Discount [Member] \| IPO [Member]
Commitments and Contingencies (Details) [Line Items]
Gross proceeds from proposed public offering				$ 1,150,000