Summary of Significant Accounting Policies (Details) (Textuals) $ in Thousands	Jan. 01, 2022 USD ($)
Accounting Changes and Error Corrections [Abstract]
Cumulative effect of accounting methodology change	$ 2,296

Cumulative effect of accounting methodology change

No definition available.

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