Securities - Securities Available-for-sale and Held-to-maturity by Contractual Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Securities held-to-maturity, amortized cost, due after ten years	$ 50,836
Securities held-to-maturity, fair value, due after ten years	53,362
Securities held-to-maturity, amortized cost	58,730
Securities held-to-maturity, allowance for credit losses	(862)	$ (907)
Securities held-to-maturity, amortized cost	57,868	57,832
Securities held-to-maturity, fair value	62,029	63,529
Securities available for sale, amortized cost, due after one years through five years	20,000
Securities available for sale, fair value, due after one years through five years	19,865
Securities available for sale, amortized cost, due after five years through ten years	163,572
Securities available for sale, fair value, due after five years through ten years	160,417
Securities available for sale, amortized cost, due after ten years	12,311
Securities available for sale, fair value, due after ten years	12,285
Securities available for sale, amortized cost, total other securities	786,425	646,112
Securities available for sale, fair value, total other securities	777,236	647,974
US States and Political Subdivisions Debt Securities [Member]
Securities held-to-maturity, amortized cost	50,836	50,825
Securities held-to-maturity, fair value	53,362	54,538
Total Other Securities [Member]
Securities held-to-maturity, amortized cost	50,836
Securities held-to-maturity, fair value	53,362
Securities available for sale, amortized cost, total other securities	195,883
Securities available for sale, fair value, total other securities	192,567
Collateralized Mortgage Backed Securities [Member]
Securities held-to-maturity, amortized cost	7,894	7,914
Securities held-to-maturity, amortized cost	7,894	7,914
Securities held-to-maturity, fair value	8,667	8,991
Securities available for sale, amortized cost, total other securities	578,057	395,101
Securities available for sale, fair value, total other securities	572,184	404,460
Mutual Fund Debt Securities [Member]
Securities available for sale, amortized cost, total other securities	12,485	12,703
Securities available for sale, fair value, total other securities	$ 12,485	$ 12,703

Amount of investment in debt security measured at amortized cost, before allowance for credit losses.

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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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Amount of allowance for credit loss for debt security measured at amortized cost (held-to-maturity).

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Amount, before allowance for credit loss, of investment in debt security measured at amortized cost (held-to-maturity).

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