XML 100 R89.htm IDEA: XBRL DOCUMENT v3.25.3

Note 13 - Business Segments (Details Textual) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)	Sep. 30, 2025 USD ($)	Sep. 30, 2024 USD ($)
Number of Bank Branches	27		27
Noninterest Expense	$ 25,388	$ 25,832	$ 75,945	$ 73,218
Number of Reportable Segments			2
Home Lending [Member] | Allocated Overhead Expense [Member]
Noninterest Expense	$ 1,800	$ 1,800	$ 5,500	$ 4,800

X

- Definition

Represents the number bank branches.

+ References

No definition available.

+ Details

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Namespace Prefix:	fsbw_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

X

- Definition

Total aggregate amount of all noninterest expense.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 220
-SubTopic 40
-Name Accounting Standards Codification
-Section 55
-Paragraph 21
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147476153/220-40-55-21

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-Topic 942
-SubTopic 220
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-04(14))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478524/942-220-S99-1

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Balance Type:	debit
Period Type:	duration

X

- Definition

Number of segments reported by the entity. A reportable segment is a component of an entity for which there is an accounting requirement to report separate financial information on that component in the entity's financial statements.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
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-Topic 280
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 18
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482810/280-10-50-18

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X

- Details

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Namespace Prefix:
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Balance Type:
Period Type:

X

- Details

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Namespace Prefix:
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Balance Type:
Period Type: