Fair Value Measurements - Schedule of Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Assets
Federal funds sold	$ 13,611	$ 33,927
Interest bearing deposits with other banks	235,819	265,272
Investment securities available-for-sale	1,474,945	1,598,666
Investment securities held-to-maturity	872,710	968,707
Federal Reserve and Federal Home Loan Bank stock	25,689	65,067
Bank owned life insurance	112,234	110,998
Liabilities
Interest bearing deposits	932,779	1,138,235
Customer repurchase agreements	25,689	35,100
Significant Other Observable Inputs (Level 2) | Credit risk participation agreements
Liabilities
Derivative liability		2
Carrying Value
Assets
Cash and due from banks	8,625	12,655
Federal funds sold	13,611	33,927
Interest bearing deposits with other banks	235,819	265,272
Investment securities available-for-sale	1,474,945	1,598,666
Investment securities held-to-maturity	1,032,485	1,093,374
Federal Reserve and Federal Home Loan Bank stock	25,689	65,067
Loans held for sale		6,734
Loans	7,916,391	7,635,632
Bank owned life insurance	112,234	110,998
Annuity investment	13,088	13,869
Accrued interest receivable	53,361	51,390
Liabilities
Noninterest bearing deposits	2,072,665	3,150,751
Interest bearing deposits	4,062,552	4,778,932
Time deposits	2,241,089	783,499
Customer repurchase agreements	25,689	35,100
Borrowings	1,369,888	1,044,795
Accrued interest payable	38,642	25,911
Carrying Value | Mortgage banking derivatives
Assets
Derivative asset		93
Carrying Value | Interest rate product
Assets
Derivative asset	41,787	31,039
Liabilities
Derivative liability	41,637	30,065
Carrying Value | Credit risk participation agreements
Assets
Derivative asset	1
Liabilities
Derivative liability		2
Fair Value
Assets
Cash and due from banks	8,625	12,655
Federal funds sold	13,611	33,927
Interest bearing deposits with other banks	235,819	265,272
Investment securities available-for-sale	1,474,945	1,598,666
Investment securities held-to-maturity	872,710	967,940
Loans held for sale		6,734
Loans	7,635,283	7,492,283
Bank owned life insurance	112,234	110,998
Annuity investment	13,088	13,869
Accrued interest receivable	53,361	51,390
Liabilities
Noninterest bearing deposits	2,072,665	3,150,751
Interest bearing deposits	4,062,552	4,778,932
Time deposits	2,225,503	777,757
Customer repurchase agreements	25,689	35,100
Borrowings	1,367,912	1,043,083
Accrued interest payable	38,642	25,911
Fair Value | Mortgage banking derivatives
Assets
Derivative asset		93
Fair Value | Interest rate product
Assets
Derivative asset	41,787	31,039
Liabilities
Derivative liability	41,637	30,065
Fair Value | Credit risk participation agreements
Assets
Derivative asset	1
Liabilities
Derivative liability		2
Fair Value | ​Quoted Prices (Level 1)
Assets
Cash and due from banks	8,625	12,655
Federal funds sold	0	0
Interest bearing deposits with other banks	0	0
Investment securities available-for-sale	0	0
Investment securities held-to-maturity	0	0
Federal Reserve and Federal Home Loan Bank stock	0	0
Loans held for sale		0
Loans	0	0
Bank owned life insurance	0	0
Annuity investment	0	0
Accrued interest receivable	53,361	51,390
Liabilities
Noninterest bearing deposits	0	0
Interest bearing deposits	0	0
Time deposits	0	0
Customer repurchase agreements	0	0
Borrowings	0	0
Accrued interest payable	38,642	25,911
Fair Value | ​Quoted Prices (Level 1) | Mortgage banking derivatives
Assets
Derivative asset		0
Fair Value | ​Quoted Prices (Level 1) | Interest rate product
Assets
Derivative asset	0	0
Liabilities
Derivative liability	0	0
Fair Value | ​Quoted Prices (Level 1) | Credit risk participation agreements
Assets
Derivative asset	0
Liabilities
Derivative liability		0
Fair Value | Significant Other Observable Inputs (Level 2)
Assets
Cash and due from banks	0	0
Federal funds sold	13,611	33,927
Interest bearing deposits with other banks	235,819	265,272
Investment securities available-for-sale	1,474,945	1,598,666
Investment securities held-to-maturity	872,710	967,940
Federal Reserve and Federal Home Loan Bank stock	0	0
Loans held for sale		6,734
Loans	0	0
Bank owned life insurance	112,234	110,998
Annuity investment	13,088	13,869
Accrued interest receivable	0	0
Liabilities
Noninterest bearing deposits	2,072,665	3,150,751
Interest bearing deposits	4,062,552	4,778,932
Time deposits	2,225,503	777,757
Customer repurchase agreements	25,689	35,100
Borrowings	1,367,912	1,043,083
Accrued interest payable	0	0
Fair Value | Significant Other Observable Inputs (Level 2) | Mortgage banking derivatives
Assets
Derivative asset		0
Fair Value | Significant Other Observable Inputs (Level 2) | Interest rate product
Assets
Derivative asset	41,787	31,039
Liabilities
Derivative liability	41,637	30,065
Fair Value | Significant Other Observable Inputs (Level 2) | Credit risk participation agreements
Assets
Derivative asset	1
Fair Value | Significant Other Unobservable Inputs (Level 3)
Assets
Cash and due from banks	0	0
Federal funds sold	0	0
Interest bearing deposits with other banks	0	0
Investment securities available-for-sale	0	0
Investment securities held-to-maturity	0	0
Federal Reserve and Federal Home Loan Bank stock	0	0
Loans held for sale		0
Loans	7,635,283	7,492,283
Bank owned life insurance	0	0
Annuity investment	0	0
Accrued interest receivable	0	0
Liabilities
Noninterest bearing deposits	0	0
Interest bearing deposits	0	0
Time deposits	0	0
Customer repurchase agreements	0	0
Borrowings	0	0
Accrued interest payable	0	0
Fair Value | Significant Other Unobservable Inputs (Level 3) | Mortgage banking derivatives
Assets
Derivative asset		93
Fair Value | Significant Other Unobservable Inputs (Level 3) | Interest rate product
Assets
Derivative asset	0	0
Liabilities
Derivative liability	0	0
Fair Value | Significant Other Unobservable Inputs (Level 3) | Credit risk participation agreements
Assets
Derivative asset	$ 0
Liabilities
Derivative liability		$ 0