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Securities - Amortized Cost and Estimated Fair Value of Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Available for sale:
Available for sale, amortized cost	$ 1,951,949	$ 1,497,458
Available for sale, gross unrealized gains	1,243	21,896
Available for sale, gross unrealized losses	(148,822)	(14,626)
Available for sale, fair value	1,804,370	1,504,728
Available for sale, allowance for credit losses	0	0
Available-for-sale, net carrying amount	1,804,370	1,504,728
Held to maturity:
Held to maturity, fair value	5,448	25,117
Held to maturity, allowance for credit losses	(892)	(167)	$ (71)	$ (66)
Held to maturity, net carrying amount	4,288	22,767
Securities carried at fair value through income:
Securities carried at fair value through income, fair value	6,630	7,497
State and municipal securities
Available for sale:
Available for sale, amortized cost	449,111	394,046
Available for sale, gross unrealized gains	1,121	14,095
Available for sale, gross unrealized losses	(48,288)	(2,323)
Available for sale, fair value	401,944	405,818
Available for sale, allowance for credit losses	0	0
Available-for-sale, net carrying amount	401,944	405,818
Held to maturity:
Held to maturity, amortized cost	5,180	22,934
Held to maturity, gross unrealized gains	268	2,183
Held to maturity, gross unrealized losses	0	0
Held to maturity, fair value	5,448	25,117
Held to maturity, allowance for credit losses	(892)	(167)
Held to maturity, net carrying amount	4,288	22,767
Securities carried at fair value through income:
Securities carried at fair value through income, amortized cost	7,100	7,375
Securities carried at fair value through income, fair value	6,630	7,497
Securities carried at fair value through income, net carrying amount	6,630	7,497
Corporate bonds
Available for sale:
Available for sale, amortized cost	82,224	80,498
Available for sale, gross unrealized gains	84	2,509
Available for sale, gross unrealized losses	(2,715)	(273)
Available for sale, fair value	79,593	82,734
Available for sale, allowance for credit losses	0	0
Available-for-sale, net carrying amount	79,593	82,734
U.S. government and agency securities
Available for sale:
Available for sale, amortized cost	268,061	98,892
Available for sale, gross unrealized gains	4	2
Available for sale, gross unrealized losses	(11,018)	(1,236)
Available for sale, fair value	257,047	97,658
Available for sale, allowance for credit losses	0	0
Available-for-sale, net carrying amount	257,047	97,658
Commercial mortgage-backed securities
Available for sale:
Available for sale, amortized cost	120,787	65,691
Available for sale, gross unrealized gains	0	0
Available for sale, gross unrealized losses	(10,090)	(1,448)
Available for sale, fair value	110,697	64,243
Available for sale, allowance for credit losses	0	0
Available-for-sale, net carrying amount	110,697	64,243
Residential mortgage-backed securities
Available for sale:
Available for sale, amortized cost	703,369	559,655
Available for sale, gross unrealized gains	31	3,751
Available for sale, gross unrealized losses	(54,274)	(5,605)
Available for sale, fair value	649,126	557,801
Available for sale, allowance for credit losses	0	0
Available-for-sale, net carrying amount	649,126	557,801
Commercial collateralized mortgage obligations
Available for sale:
Available for sale, amortized cost	44,876	20,000
Available for sale, gross unrealized gains	0	2
Available for sale, gross unrealized losses	(3,911)	(330)
Available for sale, fair value	40,965	19,672
Available for sale, allowance for credit losses	0	0
Available-for-sale, net carrying amount	40,965	19,672
Residential collateralized mortgage obligations
Available for sale:
Available for sale, amortized cost	204,801	196,691
Available for sale, gross unrealized gains	3	460
Available for sale, gross unrealized losses	(16,213)	(3,411)
Available for sale, fair value	188,591	193,740
Available for sale, allowance for credit losses	0	0
Available-for-sale, net carrying amount	188,591	193,740
Asset-backed securities
Available for sale:
Available for sale, amortized cost	78,720	81,985
Available for sale, gross unrealized gains	0	1,077
Available for sale, gross unrealized losses	(2,313)	0
Available for sale, fair value	76,407	83,062
Available for sale, allowance for credit losses	0	0
Available-for-sale, net carrying amount	$ 76,407	$ 83,062

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