Segment and Geographic Information - Net Sales of 10% or More of Total Revenues Derived from Customers (Parenthetical) (Detail)	12 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Entity Wide Revenue Major Customer [Line Items]
Percentage of net sales made to customers	10.00%	10.00%

Minimum percentage of sales required for major customer classification.

No definition available.

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