Name:	bv_BusinessCombinationPercentofUnvestedEquityAwardsConverted
Namespace Prefix:	bv_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Termination fee to be paid by the acquirer in the event the acquirer terminates the merger agreement.

No definition available.

Name:	bv_BusinessCombinationTerminationFeeAcquierer
Namespace Prefix:	bv_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Termination fee to be paid by acquiree in the event the acquiree terminates the merger agreement.

No definition available.

Name:	bv_BusinessCombinationTerminationFeeAcquiree
Namespace Prefix:	bv_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

The percentage of equity awards that are not converted into a right to receive the per share purchase price upon completion of the merger.

No definition available.

Name:	bv_BusinessCombinationUnvestedEquityAwardsNotConverted
Namespace Prefix:	bv_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Price of a single share of a number of saleable stocks paid or offered to be paid in a business combination.

No definition available.

Name:	us-gaap_BusinessAcquisitionSharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

No definition available.