XML 57 R46.htm IDEA: XBRL DOCUMENT v3.24.2.u1

Note 2 - Investments - Schedule of Debt Securities, Held-to-Maturity Credit Quality Indicators (Details) - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Debt Securities, Held-to-Maturity, Amortized Cost	$ 8.5	$ 8.5
Standard & Poor's, BBB/BBB Minus Rating [Member]
Debt Securities, Held-to-Maturity, Amortized Cost	7.0	7.0
Standard & Poor's, BB+ Rating [Member]
Debt Securities, Held-to-Maturity, Amortized Cost	$ 1.5	$ 1.5

X

- Definition

Amount, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/otherTransitionRef
-Topic 310
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 7A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481962/310-10-50-7A

Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 320
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481800/320-10-50-5

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 14
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-14

+ Details

Name:	us-gaap_HeldToMaturitySecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	srt_CreditRatingStandardPoorsAxis=fsbw_StandardPoorsBBBOrBBBMinusRatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	srt_CreditRatingStandardPoorsAxis=srt_StandardPoorsBBPlusRatingMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: