Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands		Sep. 30, 2023	Dec. 31, 2022
Recurring
Assets, Fair Value Disclosure [Abstract]
U.S. Treasury securities		$ 729,156	$ 194,184
U.S. Government agency securities		255,105	396,157
Mortgage-backed securities		887,907	971,576
State and municipal securities		1,411,123	1,412,306
Agency-backed securities		163,462	117,403
Corporate notes and other		416,944	467,244
Total investment securities available-for-sale		3,863,697	3,558,870
Other Investments		178,040	153,011
Other assets		264,118	190,629
Total assets at fair value		4,305,855	3,902,510
Liabilities at fair value: [Abstract]
Other liabilities		154,119	96,483
Total liabilities at fair value		154,119	96,483
Recurring | Quoted market prices in an active market (Level 1)
Assets, Fair Value Disclosure [Abstract]
U.S. Treasury securities		0	0
U.S. Government agency securities		0	0
Mortgage-backed securities		0	0
State and municipal securities		0	0
Agency-backed securities		0	0
Corporate notes and other		0	0
Total investment securities available-for-sale		0	0
Other Investments		0	0
Other assets		0	0
Total assets at fair value		0	0
Liabilities at fair value: [Abstract]
Other liabilities		0	0
Total liabilities at fair value		0	0
Recurring | Models with significant observable market parameters (Level 2)
Assets, Fair Value Disclosure [Abstract]
U.S. Treasury securities		729,156	194,184
U.S. Government agency securities		255,105	396,157
Mortgage-backed securities		887,907	971,576
State and municipal securities		1,410,652	1,411,677
Agency-backed securities		163,462	117,403
Corporate notes and other		416,944	467,244
Total investment securities available-for-sale		3,863,226	3,558,241
Other Investments		21,377	22,029
Other assets		264,118	190,629
Total assets at fair value		4,148,721	3,770,899
Liabilities at fair value: [Abstract]
Other liabilities		154,119	96,483
Total liabilities at fair value		154,119	96,483
Recurring | Models with significant unobservable market parameters (Level 3)
Assets, Fair Value Disclosure [Abstract]
U.S. Treasury securities		0	0
U.S. Government agency securities		0	0
Mortgage-backed securities		0	0
State and municipal securities		471	629
Agency-backed securities		0	0
Corporate notes and other		0	0
Total investment securities available-for-sale		471	629
Other Investments		156,663	130,982
Other assets		0	0
Total assets at fair value		157,134	131,611
Liabilities at fair value: [Abstract]
Other liabilities		0	0
Total liabilities at fair value		0	0
Nonrecurring
Assets, Fair Value Disclosure [Abstract]
Total assets at fair value		62,839	41,719
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Other real estate owned		2,555	7,952
Collateral dependent loans (1)	[1]	60,284	33,767
Nonrecurring | Quoted market prices in an active market (Level 1)
Assets, Fair Value Disclosure [Abstract]
Total assets at fair value		0	0
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Other real estate owned		0	0
Collateral dependent loans (1)	[1]	0	0
Nonrecurring | Models with significant observable market parameters (Level 2)
Assets, Fair Value Disclosure [Abstract]
Total assets at fair value		0	0
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Other real estate owned		0	0
Collateral dependent loans (1)	[1]	0	0
Nonrecurring | Models with significant unobservable market parameters (Level 3)
Assets, Fair Value Disclosure [Abstract]
Total assets at fair value		62,839	41,719
Fair Value Assets And Liabilities Measured On Nonrecurring Basis [Abstract]
Other real estate owned		2,555	7,952
Collateral dependent loans (1)	[1]	$ 60,284	$ 33,767

[1] The carrying values of collateral dependent loans at September 30, 2023 and December 31, 2022 are net of valuation allowances of $10.5 million and $6.5 million, respectively.