XML 8 R1.htm IDEA: XBRL DOCUMENT v3.25.1
Cover
May 29, 2025
Cover [Abstract]  
Document Type 8-K
Document Period End Date May 29, 2025
Entity Registrant Name ISABELLA BANK CORP
Entity Incorporation, State or Country Code MI
Entity File Number 000-18415
Entity Tax Identification Number 38-2830092
Entity Address, Address Line One 401 North Main Street
Entity Address, City or Town Mt. Pleasant
Entity Address, State or Province MI
Entity Address, Postal Zip Code 48858-1649
City Area Code 989
Local Phone Number 772-9471
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Title of 12(b) Security Common stock, no par value per share
Trading Symbol ISBA
Security Exchange Name NASDAQ
Entity Emerging Growth Company false
Entity Central Index Key 0000842517
Amendment Flag false