Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Interest income:
Loans, including fees	$ 182,695	$ 171,305	$ 350,178	$ 343,442
Securities:
Taxable	20,602	23,360	40,630	49,390
Tax-exempt	56,111	59,009	112,774	117,895
Interest-bearing deposits	3,614	1,257	6,047	9,382
Federal funds sold	8	33	11	716
Resell agreements	4	30	5	149
Total interest income	263,034	254,994	509,645	520,974
Interest expense:
Deposits	3,499	6,227	7,016	22,280
Federal funds purchased	7	6	15	85
Repurchase agreements	570	480	965	3,438
Junior subordinated deferrable interest debentures	638	988	1,284	2,193
Subordinated notes	1,164	1,164	2,328	2,328
Federal Home Loan Bank advances	0	318	0	318
Total interest expense	5,878	9,183	11,608	30,642
Net interest income	257,156	245,811	498,037	490,332
Credit loss expense	0	31,975	63	207,172
Net interest income after credit loss expense	257,156	213,836	497,974	283,160
Non-interest income:
Trust and investment management fees	37,874	31,060	73,188	65,533
Service charges on deposit accounts	19,849	17,580	39,842	40,231
Insurance commissions and fees	10,773	10,668	28,086	27,153
Interchange and card transaction fees	4,641	2,966	8,734	6,221
Other charges, commissions and fees	8,640	7,663	16,944	17,028
Net gain (loss) on securities transactions	0	0	0	108,989
Other	9,470	7,664	17,689	25,361
Total non-interest income	91,247	77,601	184,483	290,516
Non-interest expense:
Salaries and wages	97,035	90,350	190,493	189,162
Employee benefits	18,728	18,861	41,264	43,750
Net occupancy	26,650	25,266	52,701	50,650
Technology, furniture and equipment	27,998	26,046	56,014	51,286
Deposit insurance	2,877	2,800	5,805	5,424
Intangible amortization	185	241	387	498
Other	41,781	36,115	78,732	83,072
Total non-interest expense	215,254	199,679	425,396	423,842
Income before income taxes	133,149	91,758	257,061	149,834
Income taxes	15,081	(1,314)	22,978	2,009
Net income	118,068	93,072	234,083	147,825
Preferred stock dividends	1,669	0	3,820	2,016
Redemption of preferred stock	0	0	0	5,514
Net income available to common shareholders	$ 116,399	$ 93,072	$ 230,263	$ 140,295
Earnings per common share:
Basic	$ 1.81	$ 1.47	$ 3.59	$ 2.22
Diluted	$ 1.80	$ 1.47	$ 3.57	$ 2.21