Investment Securities - Book Values, Estimated Fair Values and Unrealized Gains and Losses of Investments Classified as Held-To-Maturity (Details) - USD ($)
$ in Thousands

Dec. 31, 2025

Dec. 31, 2024

Dec. 31, 2023

Investment Securities [Abstract]

Amortized cost

$ 718,641

$ 769,443

Gross unrecognized gains

1,099

Gross unrecognized losses

127,004

158,536

Fair value

592,736

610,953

Allowance for credit losses

450

$ 450

Mortgage-backed Securities [Member]

Investment Securities [Abstract]

Amortized cost

^[1]

586,001

626,427

Gross unrecognized gains

^[1]

Gross unrecognized losses

^[1]

115,773

143,544

Fair value

^[1]

470,316

482,883

Allowance for credit losses

^[1]

Collateralized Mortgage Obligations [Member]

Investment Securities [Abstract]

Amortized cost

^[1]

62,476

68,377

Gross unrecognized gains

^[1]

Gross unrecognized losses

^[1]

10,234

13,876

Fair value

^[1]

52,242

54,501

Allowance for credit losses

^[1]

Municipal Securities [Member]

Investment Securities [Abstract]

Amortized cost

70,164

74,639

Gross unrecognized gains

1,011

Gross unrecognized losses

997

1,116

Fair value

70,178

73,569

Allowance for credit losses

$ 450

[1]	All mortgage-backed securities and collateralized mortgage obligations were issued by an agency or government sponsored entity of the U.S. Government.

- Definition

Fair value of investment in debt security measured at amortized cost (held-to-maturity).

+ References

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+ Details

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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+ Details

FARMERS & MERCHANTS BANCORP 10-K