Consolidated Statements of Income (Unaudited) - USD ($) shares in Thousands, $ 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	$ 209,066	$ 228,917	$ 422,779	$ 467,640
Loans held for sale	648	650	1,319	1,271
Securities-taxable	33,148	31,702	64,351	64,309
Securities-tax exempt	4,762	4,854	9,545	9,798
Short-term investments	676	219	1,091	667
Total interest income	248,300	266,342	499,085	543,685
Interest expense:
Deposits	7,064	22,629	16,291	61,566
Short-term borrowings	1,555	2,253	3,088	6,715
Long-term debt	5,038	3,594	10,476	6,350
Total interest expense	13,657	28,476	29,855	74,631
Net interest income	234,643	237,866	469,230	469,054
Provision for credit losses	(17,229)	306,898	(22,140)	553,691
Net interest income (loss) after provision for credit losses	251,872	(69,032)	491,370	(84,637)
Noninterest income:
Securities transactions, net	333		333	112
Other income	17,881	13,134	33,533	29,201
Total noninterest income	94,272	73,943	181,361	158,330
Noninterest expense:
Compensation expense	100,587	98,756	196,433	189,827
Employee benefits	42,067	21,653	65,836	44,131
Personnel expense	142,654	120,409	262,269	233,958
Net occupancy expense	12,955	13,559	25,865	26,081
Equipment expense	4,392	4,752	9,173	9,369
Data processing expense	23,885	21,250	46,832	43,297
Professional services expense	13,473	10,985	24,724	20,726
Amortization of intangible assets	4,245	5,169	8,664	10,514
Deposit insurance and regulatory fees	2,967	5,116	6,362	10,931
Other real estate and foreclosed assets expense (income)	(86)	(460)	(80)	9,670
Other expense	32,285	15,759	46,033	35,328
Total noninterest expense	236,770	196,539	429,842	399,874
Income (loss) before income taxes	109,374	(191,628)	242,889	(326,181)
Income taxes expense (benefit)	20,656	(74,556)	46,999	(98,076)
Net income (loss)	$ 88,718	$ (117,072)	$ 195,890	$ (228,105)
Earnings (loss) per common share-basic	$ 1.00	$ (1.36)	$ 2.21	$ (2.64)
Earnings (loss) per common share-diluted	1.00	(1.36)	2.20	(2.64)
Dividends paid per share	$ 0.27	$ 0.27	$ 0.54	$ 0.54
Weighted average shares outstanding-basic	86,814	86,301	86,783	86,744
Weighted average shares outstanding-diluted	86,990	86,301	86,932	86,744
Service charges on deposit accounts
Noninterest income:
Service charges on deposit accounts	$ 19,381	$ 15,518	$ 38,527	$ 38,355
Trust fees
Noninterest income:
Service charges on deposit accounts	16,307	14,160	31,310	28,966
Bank card and ATM fees
Noninterest income:
Service charges on deposit accounts	20,483	15,957	38,603	33,319
Investment and annuity fees and insurance commissions
Noninterest income:
Service charges on deposit accounts	7,331	5,366	14,789	12,516
Secondary mortgage market operations
Noninterest income:
Service charges on deposit accounts	$ 12,556	$ 9,808	$ 24,266	$ 15,861