Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Interest income:
Loans, including fees	$ 204,102	$ 220,392	$ 626,881	$ 688,032
Loans held for sale	635	833	1,954	2,104
Securities-taxable	33,936	30,863	98,287	95,172
Securities-tax exempt	4,724	4,831	14,269	14,629
Short-term investments	1,020	124	2,111	791
Total interest income	244,417	257,043	743,502	800,728
Interest expense:
Deposits	5,090	14,783	21,381	76,349
Short-term borrowings	1,470	1,673	4,558	8,388
Long-term debt	3,148	5,404	13,624	11,754
Total interest expense	9,708	21,860	39,563	96,491
Net interest income	234,709	235,183	703,939	704,237
Provision for credit losses	(26,955)	24,999	(49,095)	578,690
Net interest income after provision for credit losses	261,664	210,184	753,034	125,547
Noninterest income:
Securities transactions, net		376	333	488
Other income	22,189	14,423	55,722	43,624
Total noninterest income	93,361	83,748	274,722	242,078
Noninterest expense:
Compensation expense	92,601	97,095	289,034	286,922
Employee benefits	19,377	20,761	85,213	64,892
Personnel expense	111,978	117,856	374,247	351,814
Net occupancy expense	11,974	13,191	37,839	39,272
Equipment expense	4,894	5,355	14,067	14,724
Data processing expense	24,766	21,888	71,598	65,185
Professional services expense	12,748	14,372	37,472	35,098
Amortization of intangible assets	4,082	4,788	12,746	15,302
Deposit insurance and regulatory fees	3,680	4,108	10,042	15,039
Other real estate and foreclosed assets expense (income)	(376)	(482)	(456)	9,188
Other expense	20,957	14,698	66,990	50,026
Total noninterest expense	194,703	195,774	624,545	595,648
Income (loss) before income taxes	160,322	98,158	403,211	(228,023)
Income taxes expense (benefit)	30,740	18,802	77,739	(79,274)
Net income (loss)	$ 129,582	$ 79,356	$ 325,472	$ (148,749)
Earnings (loss) per common share-basic	$ 1.46	$ 0.90	$ 3.67	$ (1.73)
Earnings (loss) per common share-diluted	1.46	0.90	3.67	(1.73)
Dividends paid per share	$ 0.27	$ 0.27	$ 0.81	$ 0.81
Weighted average shares outstanding-basic	86,834	86,358	86,800	86,614
Weighted average shares outstanding-diluted	87,006	86,400	86,951	86,614
Service charges on deposit accounts
Noninterest income:
Service charges on deposit accounts	$ 21,159	$ 18,440	$ 59,686	$ 56,795
Trust fees
Noninterest income:
Service charges on deposit accounts	16,041	14,424	47,351	43,390
Bank card and ATM fees
Noninterest income:
Service charges on deposit accounts	19,833	17,222	58,436	50,541
Investment and annuity fees and insurance commissions
Noninterest income:
Service charges on deposit accounts	7,167	5,988	21,956	18,504
Secondary mortgage market operations
Noninterest income:
Service charges on deposit accounts	$ 6,972	$ 12,875	$ 31,238	$ 28,736