Short-Term Borrowings - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Federal Funds Purchased
Short-term borrowings
Unsecured maximum borrowing capacity	$ 87.0	$ 87.0
Outstanding credit facility	0.0	0.0
FHLB short-term advances
Short-term borrowings
Outstanding credit facility	706.6	$ 531.6
Unsecured Line Of Credit With Bank of North Dakota
Short-term borrowings
Unused line of credit	$ 20.0

Amount of the fee for available but unused credit capacity under the credit facility.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19(b),22(b))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

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- Definition

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+ References

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