Note 8 - Deposits - Interest Expense on Deposits (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Interest-bearing checking	$ 9,824	$ 2,888
Savings and money market	6,970	2,610
Time deposits	7,677	1,818
Total deposit interest expense	$ 24,471	$ 7,316

The aggregate interest expense incurred on the following for deposits in domestic offices: (1) money market deposits and (2) savings deposits.

No definition available.

+ Details

Name:	atlo_InterestExpenseMoneyMarketAccountsAndSavingsDeposits
Namespace Prefix:	atlo_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Aggregate amount of interest expense on all deposits.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04.6)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483589/942-220-S99-1

+ Details

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

- Definition

Interest expense incurred on the amount of Negotiable Order of Withdrawal (NOW). Interest-bearing transaction account that combines the payable on demand feature of checks and investment feature of savings accounts. A NOW account is functionally an interest paying checking account.

+ References

+ Details

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

- Definition

Interest expense incurred on other deposits in domestic offices.

+ References

+ Details

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