Name:	asb_HeldtomaturitySecuritiesGrossRealizedGains
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This item represents the gross loss realized on the sale of debt or equity securities categorized neither as available-for-sale nor trading securities.

No definition available.

Name:	asb_HeldtomaturitySecuritiesGrossRealizedLosses
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Data Type:	xbrli:monetaryItemType
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This item represents the total gross realized gains included in earnings for the period as a result of selling marketable securities categorized as trading, available-for-sale, or held-to-maturity.

No definition available.

Name:	asb_MarketableSecuritiesGrossRealizedGain
Namespace Prefix:	asb_
Data Type:	xbrli:monetaryItemType
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This item represents the total realized loss included in earnings for the period as a result of selling marketable securities categorized as trading, available-for-sale, or held-to-maturity.

No definition available.

Name:	asb_MarketableSecuritiesRealizedLoss
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The cash inflow associated with the sale of securities that had been designated as either held-to-maturity or available-for-sale. Excludes proceeds from maturities, prepayments and calls by the issuer.

No definition available.

Name:	asb_ProceedsfromSaleofSecurities
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Data Type:	xbrli:monetaryItemType
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- References

No definition available.

Name:	us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNetAbstract
Namespace Prefix:	us-gaap_
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This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563

Name:	us-gaap_AvailableForSaleSecuritiesGrossRealizedGains
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

This item represents the gross loss realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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

This item represents the total realized gain (loss) included in earnings for the period as a result of selling marketable securities categorized as trading, available-for-sale, or held-to-maturity. Additionally, this item would include any losses recognized for other than temporary impairments (OTTI) of the subject investments in debt and equity securities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.7(c))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27405-111563