Note 3 - Investment Securities - Schedule of Investment Securities (Details) (Parentheticals) - US Government Agencies Debt Securities [Member]	3 Months Ended	12 Months Ended
Mar. 31, 2024	Dec. 31, 2023
Minimum [Member]
Maturity date	Apr. 01, 2024	Jan. 01, 2024
Maximum [Member]
Maturity date	Sep. 30, 2024	Jun. 30, 2024

Date of maturity of investment in debt security measured at amortized cost (held-to-maturity), in YYYY-MM-DD format.

No definition available.

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