Investment Securities - Amortized Cost, Gross Unrealized Gains and Losses and Fair Value of Debt Securities Available for Sale (Details) - USD ($) $ in Thousands	Mar. 31, 2023	Dec. 31, 2022
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	$ 1,412,007	$ 1,437,911
Gross Unrealized Gains	106	111
Gross Unrealized Losses	(152,877)	(176,625)
Fair Value	1,259,236	1,261,397
U.S. Treasury securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	309,524	308,137
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(22,779)	(28,639)
Fair Value	286,745	279,498
U.S. government agency securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	28,394	29,494
Gross Unrealized Gains	46	47
Gross Unrealized Losses	(2,088)	(2,577)
Fair Value	26,352	26,964
Obligations of states and state agencies
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	10,649	10,899
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(652)	(493)
Fair Value	9,997	10,406
Municipal bonds
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	171,219	171,586
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(28,441)	(35,181)
Fair Value	142,778	136,405
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	181,868	182,485
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(29,093)	(35,674)
Fair Value	152,775	146,811
Residential mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	699,214	719,868
Gross Unrealized Gains	60	64
Gross Unrealized Losses	(79,498)	(90,114)
Fair Value	619,776	629,818
Corporate and other debt securities
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	193,007	197,927
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(19,419)	(19,621)
Fair Value	$ 173,588	$ 178,306

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).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563

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Amount, before tax, of unrealized loss 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).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=126970911&loc=d3e27161-111563

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- Definition

Amortized cost excluding accrued interest, after allowance for credit loss, of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI https://asc.fasb.org/extlink&oid=124258926&loc=SL82898722-210454

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Amount excluding accrued interest, 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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