Securities - Fair Value of Securities (Detail) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Available for sale
Total amortized cost	$ 1,153,611	$ 1,090,363
Gross Unrealized Gains	16,800	43,985
Gross Unrealized Losses	(9,599)	(323)
Fair Value	1,160,812	1,134,025
Held to maturity
Amortized Cost	1,552,443	168,676
Gross Unrealized Gains	20,954	11,314
Gross Unrealized Losses	(13,406)	0
Fair Value	1,559,991	179,990
U.S. Treasury and federal agencies
Available for sale
Total amortized cost	118,595	19,750
Gross Unrealized Gains	82	0
Gross Unrealized Losses	(1,698)	(35)
Fair Value	116,979	19,715
Held to maturity
Amortized Cost	195,429
Gross Unrealized Gains	12
Gross Unrealized Losses	(1,215)
Fair Value	194,226
State and municipal
Available for sale
Total amortized cost	632,652	803,100
Gross Unrealized Gains	12,802	35,014
Gross Unrealized Losses	(5,708)	(271)
Fair Value	639,746	837,843
Held to maturity
Amortized Cost	862,461	157,421
Gross Unrealized Gains	20,719	11,035
Gross Unrealized Losses	(4,263)	0
Fair Value	878,917	168,456
Federal agency collateralized mortgage obligations
Available for sale
Total amortized cost	60,600	144,022
Gross Unrealized Gains	989	3,448
Gross Unrealized Losses	(12)	(17)
Fair Value	61,577	147,453
Held to maturity
Amortized Cost	48,482	2,661
Gross Unrealized Gains	3	36
Gross Unrealized Losses	(1,020)	0
Fair Value	47,465	2,697
Federal agency mortgage–backed pools
Available for sale
Total amortized cost	225,329	114,484
Gross Unrealized Gains	1,777	4,315
Gross Unrealized Losses	(1,032)	0
Fair Value	226,074	118,799
Held to maturity
Amortized Cost	188,426	8,594
Gross Unrealized Gains	151	243
Gross Unrealized Losses	(2,612)	0
Fair Value	185,965	8,837
Private labeled mortgage–backed pools
Available for sale
Total amortized cost	31,856
Gross Unrealized Gains	137
Gross Unrealized Losses	(376)
Fair Value	31,617	0
Held to maturity
Amortized Cost	99,958	0
Gross Unrealized Gains	58
Gross Unrealized Losses	(1,840)
Fair Value	98,176	0
Corporate notes
Available for sale
Total amortized cost	84,579	9,007
Gross Unrealized Gains	1,013	1,208
Gross Unrealized Losses	(773)	0
Fair Value	84,819	$ 10,215
Held to maturity
Amortized Cost	157,687
Gross Unrealized Gains	11
Gross Unrealized Losses	(2,456)
Fair Value	$ 155,242

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on 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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