Additional environmental remediation expense.

No definition available.

Name:	bzc_AdditionalEnvironmentalRemediationExpense
Namespace Prefix:	bzc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Additional liquidated amount.

+ References

No definition available.

+ Details

Name:	bzc_AdditionalLiquidatedAmount
Namespace Prefix:	bzc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Aggregate environmental liability.

+ References

No definition available.

+ Details

Name:	bzc_AggregateEnvironmentalLiability
Namespace Prefix:	bzc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Cost sharing environmental liabilities.

+ References

No definition available.

+ Details

Name:	bzc_CostSharingEnvironmentalLiabilities
Namespace Prefix:	bzc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Environmental remediation time frame.

+ References

No definition available.

+ Details

Name:	bzc_EnvironmentalRemediationTimeFrame
Namespace Prefix:	bzc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of environmental costs paid by federal government.

+ References

No definition available.

+ Details

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

- Definition

Percentage of environmental response costs payable.

+ References

No definition available.

+ Details

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

- Definition

Percentage of environmental response costs payable thereafter.

+ References

No definition available.

+ Details

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

- Definition

Reduced purchase price.

+ References

No definition available.

+ Details

Name:	bzc_ReducedPurchasePrice
Namespace Prefix:	bzc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Sale of environmental remediation property.

+ References

No definition available.

+ Details

Name:	bzc_SaleOfEnvironmentalRemediationProperty
Namespace Prefix:	bzc_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Number of locations for participating in environmental assessments and remediation work.

+ References

No definition available.

+ Details

Name:	bzc_SiteContingencyNumberOfLocations
Namespace Prefix:	bzc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The charge against earnings in the period for known or estimated future costs arising from requirements to perform environmental remediation activities.

+ References

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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 410

-SubTopic 30

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13296-110859

+ Details

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

- Definition

Other increase (decrease) not attributable to current expense nor cash payments during an accounting period in estimated obligations recorded for probable future costs attributable to environmental contamination issues.

+ References

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

+ Details

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

- Definition

Carrying amount as of the balance sheet date of investments in land and buildings held for sale, excluding real estate considered to be inventory of the entity.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.1(f))

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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

- Details

Name:	us-gaap_SiteContingencyLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_EnvironmentalRemediationSiteAxis=bzc_FederalLabsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_EnvironmentalRemediationSiteAxis=bzc_GlenHeadNewYorkMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_EnvironmentalRemediationSiteAxis=bzc_OtherPropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Contingencies and Legacy Environmental Commitments - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended			1 Months Ended				3 Months Ended
	Mar. 31, 2015 Location	Mar. 31, 2014	Mar. 31, 2013	Jul. 31, 2001	Mar. 31, 2015	Jun. 30, 2014	Mar. 31, 2014	Jun. 30, 2005	Dec. 31, 2003	Jun. 30, 1999	Mar. 31, 2012
Site Contingency [Line Items]
Aggregate environmental liability	$ 9,255bzc_AggregateEnvironmentalLiability	$ 10,323bzc_AggregateEnvironmentalLiability	$ 12,684bzc_AggregateEnvironmentalLiability		$ 9,255bzc_AggregateEnvironmentalLiability		10,323bzc_AggregateEnvironmentalLiability				$ 13,535bzc_AggregateEnvironmentalLiability
Cost-sharing related to environmental liabilities	1,554bzc_CostSharingEnvironmentalLiabilities	1,918bzc_CostSharingEnvironmentalLiabilities			1,554bzc_CostSharingEnvironmentalLiabilities		1,918bzc_CostSharingEnvironmentalLiabilities
Environmental costs	946us-gaap_EnvironmentalRemediationExpense	1,487us-gaap_EnvironmentalRemediationExpense	1,245us-gaap_EnvironmentalRemediationExpense
Number of locations for participating in environmental assessments and remediation work	7bzc_SiteContingencyNumberOfLocations
Time frame for environmental liabilities	30 years
Real estate held for sale	3,800us-gaap_RealEstateHeldforsale	3,800us-gaap_RealEstateHeldforsale			3,800us-gaap_RealEstateHeldforsale		3,800us-gaap_RealEstateHeldforsale
Decrease in environmental reserve	412	1,207
Glen Head, New York
Site Contingency [Line Items]
Aggregate environmental liability	3,167				3,167
Real estate held for sale	3,800				3,800
Sale of environmental remediation property				4,000
Additional liquidated amount	750				750
Glen Head, New York \| Minimum
Site Contingency [Line Items]
Reduced purchase price					0
Glen Head, New York \| Maximum
Site Contingency [Line Items]
Reduced purchase price					1,000
Federal Labs
Site Contingency [Line Items]
Aggregate environmental liability	4,153				4,153
Environmental costs									200
Additional environmental remediation expense									200
Percentage of environmental costs paid by Federal Government								45.00%		50.00%
Decrease in environmental reserve						412
Percentage of environmental costs payable							26.00%
Percentage of environmental costs payable thereafter							33.50%
Federal Labs \| Minimum
Site Contingency [Line Items]
Time frame for environmental liabilities	20 years
Federal Labs \| Maximum
Site Contingency [Line Items]
Time frame for environmental liabilities	30 years
Other Properties
Site Contingency [Line Items]
Aggregate environmental liability	$ 1,935				$ 1,935