Investment Securities - Contractual Maturity (Details) $ in Thousands	Mar. 31, 2026 USD ($)
Investment Securities [Abstract]
Available-for-sale, Amortized cost, One year or less	$ 10,659
Available-for-sale, Fair value, One year or less	10,673
Held-to-maturity, Amortized cost, One year or less	2,108
Held-to-maturity, Fair value, One year or less	2,107
Available-for-sale, Amortized cost, After one year through five years	20,371
Available-for-sale, Fair value, After one year through five years	20,417
Held-to-maturity, Amortized cost, After one year through five years	18,044
Held-to-maturity, Fair value, After one year through five years	17,977
Available-for-sale, Amortized cost, After five years through ten years	44,050
Available-for-sale, Fair value, After five years through ten years	44,698
Held-to-maturity, Amortized cost, After five years through ten years	17,983
Held-to-maturity, Fair value, After five years through ten years	17,196
Available-for-sale, Amortized cost, After ten years	840,615
Available-for-sale, Fair value, After ten years	826,127
Held-to-maturity, Amortized cost, After ten years	670,138
Held-to-maturity, Fair value, After ten years	544,234
Available-for-sale, Amortized cost, Total	915,695
Available-for-sale, Fair value, Total	901,915
Held-to-maturity, Amortized cost, Total	708,273
Held-to-maturity, Fair value, Total	$ 581,514