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Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Securities - Securities Available-for-sale and Held-to-maturity by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020
Securities held-to-maturity, amortized cost, due in one year or less	$ 10,026
Securities held-to-maturity, fair value, due in one year or less	9,920
Securities held-to-maturity, amortized cost, due after ten years	67,315
Securities held-to-maturity, fair value, due after ten years	57,064
Securities held-to-maturity, amortized cost	75,200
Securities held-to-maturity, allowance for credit losses	(1,085)	$ (986)	$ (862)	$ (844)	$ (915)	$ (907)
Securities held-to-maturity, amortized cost	74,115		57,868
Securities held-to-maturity, fair value	64,560		62,029
Securities available for sale, amortized cost, due after one years through five years	99,429
Securities available for sale, fair value, due after one years through five years	96,645
Securities available for sale, amortized cost, due after five years through ten years	205,672
Securities available for sale, fair value, due after five years through ten years	193,191
Securities available for sale, amortized cost, due after ten years	36,019
Securities available for sale, fair value, due after ten years	35,391
Securities available for sale, amortized cost, total other securities	930,362		786,425
Securities available for sale, fair value, total other securities	857,654		777,236
US States and Political Subdivisions Debt Securities [Member]
Securities held-to-maturity, amortized cost	67,315		50,836
Securities held-to-maturity, fair value	57,064		53,362
Total Other Securities [Member]
Securities held-to-maturity, amortized cost	67,315
Securities held-to-maturity, fair value	57,064
Securities available for sale, amortized cost, total other securities	351,146
Securities available for sale, fair value, total other securities	335,147
Collateralized Mortgage Backed Securities [Member]
Securities held-to-maturity, amortized cost	7,885		7,894
Securities held-to-maturity, amortized cost	7,885		7,894
Securities held-to-maturity, fair value	7,496		8,667
Securities available for sale, amortized cost, total other securities	567,643		578,057
Securities available for sale, fair value, total other securities	510,934		572,184
Mutual Fund Debt Securities [Member]
Securities available for sale, amortized cost, total other securities	11,573		12,485
Securities available for sale, fair value, total other securities	$ 11,573		$ 12,485