Unpaid Principal Balance of Residential and Consumer Loans Based on Accrual Status (Parenthetical) (Detail)	12 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Financing Receivable, Impaired [Line Items]
Period of education loans	90 days
Guarantee provided by government agencies against outstanding balances of education loans	97.00%	97.00%

Guarantee provided by government agencies against outstanding balances of education loans.

No definition available.

Name:	abcw_GuaranteeProvidedByGovernmentAgenciesAgainstOutstandingBalancesOfEducationLoans
Namespace Prefix:	abcw_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration