Label	Element	Value
Common Stock [Member]
Business Combination, Consideration Transferred, Equity Interest, Share Issued, Number of Shares	us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued	22,975,382
BusinessAcquisitionEquityInterestIssuedOrIssuableExchangeRatio	asb_BusinessAcquisitionEquityInterestIssuedOrIssuableExchangeRatio	$ 36.250
Business Combination, Consideration Transferred	us-gaap_BusinessCombinationConsiderationTransferred1	$ 594,100,000
Share Price	us-gaap_SharePrice	$ 25.86
Subsequent Event [Member]
Business Combination, Effective Date of Acquisition	us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1	Apr. 01, 2026

BusinessAcquisitionEquityInterestIssuedOrIssuableExchangeRatio

No definition available.

Name:	asb_BusinessAcquisitionEquityInterestIssuedOrIssuableExchangeRatio
Namespace Prefix:	asb_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

Date when acquirer obtains control of acquiree in business combination, in YYYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479328/805-10-50-8

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
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-Name Accounting Standards Codification
-Section 55
-Paragraph 38
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479303/805-10-55-38

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479328/805-10-50-2

Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 25
-Paragraph 7
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479405/805-10-25-7

Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 25
-Paragraph 6
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479405/805-10-25-6

+ Details

Name:	us-gaap_BusinessAcquisitionEffectiveDateOfAcquisition1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares of equity interest issued or issuable by acquirer as part of consideration transferred in business combination.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479328/805-10-50-8

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 41
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479303/805-10-55-41

Reference 3: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 30
-Name Accounting Standards Codification
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-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479581/805-30-50-2

Reference 4: http://www.xbrl.org/2003/role/exampleRef
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-Subparagraph (b)(4)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479581/805-30-50-1

Reference 5: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 42
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479303/805-10-55-42

+ Details

Name:	us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 8
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479328/805-10-50-8

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 805
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 41
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479303/805-10-55-41

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479581/805-30-50-2

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479581/805-30-50-1

+ Details

Name:	us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_BusinessAcquisitionAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: