Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	$ 1,165,310	$ 547,711
Gross Unrealized Gains	26,099	28,395
Gross Unrealized Losses	(8,048)	(506)
Fair Value	1,183,361	575,600
U.S. Treasury and U.S. government sponsored entities
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	89,919	11,798
Gross Unrealized Gains	53	101
Gross Unrealized Losses	(1,502)	(54)
Fair Value	88,470	11,845
State and political subdivisions
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	485,125	344,160
Gross Unrealized Gains	22,776	22,350
Gross Unrealized Losses	(618)	(204)
Fair Value	507,283	366,306
Mortgage-backed securities - residential
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	569,235	157,106
Gross Unrealized Gains	2,778	4,919
Gross Unrealized Losses	(5,909)	(243)
Fair Value	566,104	161,782
Collateralized mortgage obligations - residential
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	12,956	25,654
Gross Unrealized Gains	290	742
Gross Unrealized Losses	(5)	(3)
Fair Value	13,241	26,393
Corporate bonds
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	3,604	3,582
Gross Unrealized Gains	77	132
Gross Unrealized Losses	(14)	(2)
Fair Value	3,667	3,712
Small Business Administration
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost	4,471	5,411
Gross Unrealized Gains	125	151
Gross Unrealized Losses	0	0
Fair Value	$ 4,596	$ 5,562