Fair Value Measurements - Schedule of Carrying Amount and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Financial Assets:
Securities - held-to-maturity	$ 268,283	$ 0
FHLB and other stock	10,366	16,382
Financial Liabilities:
Time deposits	675,499	746,234
under agreements to repurchase	72,490	65,845
Other borrowings	110,000	265,000
Trust preferred debentures	0	13,220
Level 1
Financial Assets:
Cash and cash equivalents	333,487	388,462
Securities - held-to-maturity	0
FHLB and other stock	0	0
Accrued interest receivable	0	0
Loans/leases, net	0	0
Financial Liabilities:
Time deposits	0	0
Other deposits	0	0
under agreements to repurchase	0	0
Other borrowings	0	0
Trust preferred debentures	0	0
Accrued interest payable	0	0
Level 2
Financial Assets:
Cash and cash equivalents	0	0
Securities - held-to-maturity	268,283
FHLB and other stock	10,366	16,382
Accrued interest receivable	23,350	32,025
Loans/leases, net	0	22,171
Financial Liabilities:
Time deposits	679,335	753,045
Other deposits	6,415,399	5,691,518
under agreements to repurchase	72,490	65,845
Other borrowings	112,573	274,238
Trust preferred debentures	0	18,483
Accrued interest payable	900	1,727
Level 3
Financial Assets:
Cash and cash equivalents	0	0
Securities - held-to-maturity	0
FHLB and other stock	0	0
Accrued interest receivable	0	0
Loans/leases, net	5,072,855	5,204,130
Financial Liabilities:
Time deposits	0	0
Other deposits	0	0
under agreements to repurchase	0	0
Other borrowings	0	0
Trust preferred debentures	0	0
Accrued interest payable	0	0
Carrying Amount
Financial Assets:
Cash and cash equivalents	333,487	388,462
Securities - held-to-maturity	269,268
FHLB and other stock	10,366	16,382
Accrued interest receivable	23,350	32,025
Loans/leases, net	5,050,519	5,208,658
Financial Liabilities:
Time deposits	675,499	746,234
Other deposits	6,415,399	5,691,518
under agreements to repurchase	72,490	65,845
Other borrowings	110,000	265,000
Trust preferred debentures	0	13,220
Accrued interest payable	900	1,727
Fair Value
Financial Assets:
Cash and cash equivalents	333,487	388,462
Securities - held-to-maturity	268,283
FHLB and other stock	10,366	16,382
Accrued interest receivable	23,350	32,025
Loans/leases, net	5,072,855	5,226,301
Financial Liabilities:
Time deposits	679,335	753,045
Other deposits	6,415,399	5,691,518
under agreements to repurchase	72,490	65,845
Other borrowings	112,573	274,238
Trust preferred debentures	0	18,483
Accrued interest payable	$ 900	$ 1,727