Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Interest income:
Loans, including fees	$ 228,917	$ 243,233	$ 467,640	$ 481,515
Loans held for sale	650	344	1,271	597
Securities-taxable	31,702	30,244	64,309	61,383
Securities-tax exempt	4,854	5,211	9,798	10,657
Short-term investments	219	1,346	667	2,509
Total interest income	266,342	280,378	543,685	556,661
Interest expense:
Deposits	22,629	49,843	61,566	95,981
Short-term borrowings	2,253	7,847	6,715	15,929
Long-term debt	3,594	2,820	6,350	5,629
Total interest expense	28,476	60,510	74,631	117,539
Net interest income	237,866	219,868	469,054	439,122
Provision for credit losses	306,898	8,088	553,691	26,131
Net interest income (loss) after provision for credit losses	(69,032)	211,780	(84,637)	412,991
Noninterest income:
Other income	13,134	14,980	29,313	24,448
Total noninterest income	73,943	79,250	158,330	149,753
Noninterest expense:
Compensation expense	98,756	87,747	189,827	171,715
Employee benefits	21,653	18,888	44,131	38,618
Personnel expense	120,409	106,635	233,958	210,333
Net occupancy expense	13,559	12,961	26,081	24,945
Equipment expense	4,752	4,342	9,369	9,021
Data processing expense	21,250	20,088	43,297	39,419
Professional services expense	10,985	9,665	20,726	17,833
Amortization of intangible assets	5,169	5,047	10,514	10,185
Deposit insurance and regulatory fees	5,116	4,755	10,931	10,161
Other real estate and foreclosed asset (income) expense	(460)	395	9,670	(596)
Other expense	15,759	19,679	35,328	37,966
Total noninterest expense	196,539	183,567	399,874	359,267
Income (loss) before income taxes	(191,628)	107,463	(326,181)	203,477
Income taxes expense (benefit)	(74,556)	19,186	(98,076)	36,036
Net income (loss)	$ (117,072)	$ 88,277	$ (228,105)	$ 167,441
Earnings (loss) per common share-basic	$ (1.36)	$ 1.01	$ (2.64)	$ 1.92
Earnings (loss) per common share-diluted	(1.36)	1.01	(2.64)	1.92
Dividends paid per share	$ 0.27	$ 0.27	$ 0.54	$ 0.54
Weighted average shares outstanding-basic	86,301	85,728	86,744	85,708
Weighted average shares outstanding-diluted	86,301	85,835	86,744	85,810
Service charges on deposit accounts
Noninterest income:
Service charges on deposit accounts	$ 15,518	$ 20,723	$ 38,355	$ 41,090
Trust fees
Noninterest income:
Service charges on deposit accounts	14,160	15,904	28,966	31,028
Bank card and ATM fees
Noninterest income:
Service charges on deposit accounts	15,957	16,619	33,319	31,909
Investment and annuity fees and insurance commissions
Noninterest income:
Service charges on deposit accounts	5,366	6,591	12,516	13,119
Secondary mortgage market operations
Noninterest income:
Service charges on deposit accounts	$ 9,808	$ 4,433	$ 15,861	$ 8,159