Mortgage Servicing Rights - Additional Information (Detail) - USD ($) $ in Billions	9 Months Ended
Sep. 30, 2015	Dec. 31, 2014
Transfers and Servicing [Abstract]
Assumed amortization rate of mortgage servicing rights	19.50%
Unpaid principal balance of mortgage loans serviced for others	$ 2.3	$ 2.5

Unpaid principal balance of mortgage loans serviced for others.

No definition available.

Name:	abcw_UnpaidPrincipalBalanceOfMortgageLoansServicedForOthers
Namespace Prefix:	abcw_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant