Name:	asb_LoansandLeasesReceivableNetofDeferredIncomePurchasedCreditImpairedLoansAndCoveredLoans
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Percent of Loans

No definition available.

Name:	asb_PercentofLoans
Namespace Prefix:	asb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

Restructured Loans Subsequently Accruing

No definition available.

Name:	asb_RestructuredLoansSubsequentlyAccruing
Namespace Prefix:	asb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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UnaccretedPurchaseDiscount

No definition available.

Name:	asb_UnaccretedPurchaseDiscount
Namespace Prefix:	asb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Unaccreted Purchase Discount NonPerforming Loans

No definition available.

Name:	asb_UnaccretedPurchaseDiscount_NonPerformingLoans
Namespace Prefix:	asb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Unaccreted Purchase Discount Performing Loans

No definition available.

Name:	asb_UnaccretedPurchaseDiscount_PerformingLoans
Namespace Prefix:	asb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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Ytd Restructured Loans Still On Nonaccrual

No definition available.

Name:	asb_YtdRestructuredLoansStillOnNonaccrual
Namespace Prefix:	asb_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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

Post-modification amount of investment in financing receivables modified by troubled debt restructurings.

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-Name Accounting Standards Codification
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-Section 50
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Amount of allowance to cover probable credit losses on loans and leases. Includes carryover of or adjustments to the allowance for loan losses in connection with business combinations. Excludes allowance for loans and leases covered under loss sharing agreements.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Name:	us-gaap_LoansAndLeasesReceivableAllowance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.