Investment Securities - Securities With Unrealized Losses (Details) $ in Thousands	Dec. 31, 2022 USD ($)
Available-for-sale
Available-for-sale, less than 12 months, estimated fair value	$ 1,081,117
Available-for-sale, less than 12 months, gross unrealized losses	(66,901)
Available-for-sale, 12 months or more, estimated fair value	2,715,164
Available-for-sale, 12 months or more, gross unrealized losses	(412,031)
Available-for-sale, total, estimated fair value	3,796,281
Available-for-sale, total, gross unrealized losses	(478,932)
U.S. Treasury
Available-for-sale
Available-for-sale, less than 12 months, estimated fair value	2,197
Available-for-sale, less than 12 months, gross unrealized losses	(60)
Available-for-sale, 12 months or more, estimated fair value	0
Available-for-sale, 12 months or more, gross unrealized losses	0
Available-for-sale, total, estimated fair value	2,197
Available-for-sale, total, gross unrealized losses	(60)
U.S. Government agencies
Available-for-sale
Available-for-sale, less than 12 months, estimated fair value	101,138
Available-for-sale, less than 12 months, gross unrealized losses	(3,263)
Available-for-sale, 12 months or more, estimated fair value	66,970
Available-for-sale, 12 months or more, gross unrealized losses	(4,059)
Available-for-sale, total, estimated fair value	168,108
Available-for-sale, total, gross unrealized losses	(7,322)
Mortgage-backed securities
Available-for-sale
Available-for-sale, less than 12 months, estimated fair value	653,288
Available-for-sale, less than 12 months, gross unrealized losses	(27,437)
Available-for-sale, 12 months or more, estimated fair value	1,880,277
Available-for-sale, 12 months or more, gross unrealized losses	(239,000)
Available-for-sale, total, estimated fair value	2,533,565
Available-for-sale, total, gross unrealized losses	(266,437)
State and political subdivisions
Available-for-sale
Available-for-sale, less than 12 months, estimated fair value	147,989
Available-for-sale, less than 12 months, gross unrealized losses	(24,740)
Available-for-sale, 12 months or more, estimated fair value	692,478
Available-for-sale, 12 months or more, gross unrealized losses	(160,560)
Available-for-sale, total, estimated fair value	840,467
Available-for-sale, total, gross unrealized losses	(185,300)
Other securities
Available-for-sale
Available-for-sale, less than 12 months, estimated fair value	176,505
Available-for-sale, less than 12 months, gross unrealized losses	(11,401)
Available-for-sale, 12 months or more, estimated fair value	75,439
Available-for-sale, 12 months or more, gross unrealized losses	(8,412)
Available-for-sale, total, estimated fair value	251,944
Available-for-sale, total, gross unrealized losses	$ (19,813)

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for more than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for 12 months or longer, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

+ References

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in continuous unrealized loss position for less than 12 months, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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Amount of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position without allowance for credit loss.

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Amount of accumulated unrealized loss on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset.

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