XML 10 R1.htm IDEA: XBRL DOCUMENT v3.21.1
Document and Entity Information
Mar. 30, 2021
Document and Entity Information [Abstract]  
Document Type 8-K
Document Period End Date Mar. 30, 2021
Entity File Number 001-39036
Entity Registrant Name Alerus Financial Corporation
Entity Incorporation, State or Country Code DE
Entity Tax Identification Number 45-0375407
Entity Address, Address Line One Delaware
Entity Address, City or Town Grand Forks
Entity Address, State or Province ND
Entity Address, Postal Zip Code 58201
City Area Code 701
Local Phone Number 795-3200
Written Communications false
Soliciting Material false
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Entity Emerging Growth Company true
Entity Ex Transition Period false
Entity Central Index Key 0000903419
Amendment Flag false