Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Interest income:
Loans, including fees	$ 167,483	$ 172,137
Securities:
Taxable	20,028	26,030
Tax-exempt	56,663	58,886
Interest-bearing deposits	2,433	8,125
Federal funds sold	3	683
Resell agreements	1	119
Total interest income	246,611	265,980
Interest expense:
Deposits	3,517	16,053
Federal funds purchased	8	79
Repurchase agreements	395	2,958
Junior subordinated deferrable interest debentures	646	1,205
Subordinated notes	1,164	1,164
Total interest expense	5,730	21,459
Net interest income	240,881	244,521
Credit loss expense	63	175,197
Net interest income after credit loss expense	240,818	69,324
Non-interest income:
Trust and investment management fees	35,314	34,473
Service charges on deposit accounts	19,993	22,651
Insurance commissions and fees	17,313	16,485
Interchange and card transaction fees	4,093	3,255
Other charges, commissions and fees	8,304	9,365
Net gain (loss) on securities transactions	0	108,989
Other	8,219	17,697
Total non-interest income	93,236	212,915
Non-interest expense:
Salaries and wages	93,458	98,812
Employee benefits	22,536	24,889
Net occupancy	26,051	25,384
Technology, furniture and equipment	28,016	25,240
Deposit insurance	2,928	2,624
Intangible amortization	202	257
Other	36,951	46,957
Total non-interest expense	210,142	224,163
Income before income taxes	123,912	58,076
Income taxes	7,897	3,323
Net income	116,015	54,753
Preferred stock dividends	2,151	2,016
Redemption of preferred stock	0	5,514
Net income available to common shareholders	$ 113,864	$ 47,223
Earnings per common share:
Basic	$ 1.78	$ 0.75
Diluted	$ 1.77	$ 0.75