Segment, Geographic Location, and Customer Information - Summary of Total Revenues Derived from Customers (Parenthetical) (Detail)	9 Months Ended
Dec. 31, 2012
Revenue, Major Customer [Line Items]
Net sales	10.00%

Entity Wide Revenue By Major Customer Percent Less Than Ten

No definition available.

Name:	bzc_EntityWideRevenueByMajorCustomerPercentLessThanTen
Namespace Prefix:	bzc_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration