Name:	blvdu_DeferredUnderwritingFees
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Period Type:	duration

Represents the net cash inflow or outflow during the period for the aggregate increase (decrease) associated with funds that are not available for withdrawal or use and the amount of cash outflow used to acquire short-term held-to-maturity securities during the reporting period.

No definition available.

Name:	blvdu_IncreaseDecreaseInRestrictedCashAndPaymentsToAcquireHeldToMaturitySecurities
Namespace Prefix:	blvdu_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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Represents the cash inflow from the underwriter's partial exercise of their over-allotment option during the period.

No definition available.

Name:	blvdu_ProceedsFromUnderwritersPartialExerciseOfTheirOverAllotmentOption
Namespace Prefix:	blvdu_
Data Type:	xbrli:monetaryItemType
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Period Type:	duration

Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Excludes cash and cash equivalents within disposal group and discontinued operation.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash

-URI http://asc.fasb.org/extlink&oid=6506951

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.1)

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

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

The increase (decrease) during the reporting period in the aggregate amount of expenses incurred but not yet paid.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

Name:	us-gaap_IncreaseDecreaseInAccruedLiabilities
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Data Type:	xbrli:monetaryItemType
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The increase (decrease) during the reporting period of all taxes owed but not paid, including income, property and other taxes.

No definition available.

Name:	us-gaap_IncreaseDecreaseInAccruedTaxesPayable
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Data Type:	xbrli:monetaryItemType
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The increase (decrease) during the reporting period in the aggregate amount of obligations to be paid to the following types of related parties: a parent company and its subsidiaries; subsidiaries of a common parent; an entity and trust for the benefit of employees, such as pension and profit-sharing trusts that are managed by or under the trusteeship of the entities' management; an entity and its principal owners, management, or member of their immediate families, affiliates, or other parties with the ability to exert significant influence.

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

Name:	us-gaap_IncreaseDecreaseInOperatingCapitalAbstract
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Data Type:	xbrli:stringItemType
Balance Type:	na
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The increase (decrease) during the reporting period in the amount of outstanding money paid in advance for goods or services that bring economic benefits for future periods.

Name:	us-gaap_IncreaseDecreaseInPrepaidExpense
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

The increase (decrease) in cash associated with the entity's continuing operating, investing, and financing activities. While for technical reasons this element has no balance attribute, the default assumption is a debit balance consistent with its label.

No definition available.

Name:	us-gaap_NetCashProvidedByUsedInContinuingOperations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration

Amount of cash inflow (outflow) of financing activities, excluding discontinued operations. Financing activity cash flows include obtaining resources from owners and providing them with a return on, and a return of, their investment; borrowing money and repaying amounts borrowed, or settling the obligation; and obtaining and paying for other resources obtained from creditors on long-term credit.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 24

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3521-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 26

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3574-108585

Name:	us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations
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Name:	us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract
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Name:	us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract
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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of cash inflow (outflow) from operating activities, excluding discontinued operations. Operating activity cash flows include transactions, adjustments, and changes in value not defined as investing or financing activities.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 24

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3521-108585

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 25

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3536-108585

Name:	us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperations
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Name:	us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 45

-Paragraph 11

-URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e1377-109256

Name:	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic
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Data Type:	xbrli:monetaryItemType
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The cash outflow for cost incurred directly with the issuance of an equity security.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3291-108585

Name:	us-gaap_PaymentsOfStockIssuanceCosts
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Data Type:	xbrli:monetaryItemType
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The cash inflow associated with the amount received from entity's first offering of stock to the public.

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585

Name:	us-gaap_ProceedsFromIssuanceInitialPublicOffering
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The cash inflow from issuance of rights to purchase common shares at predetermined price (usually issued together with corporate debt).

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3255-108585

Name:	us-gaap_ProceedsFromIssuanceOfWarrants
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration