Condensed Consolidated Statements of Income - USD ($) shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Interest income:
Loans, including fees	$ 312,856,000	$ 246,065,000	$ 818,473,000	$ 752,209,000
Investment securities:
Taxable	39,300,000	20,410,000	108,368,000	53,165,000
Tax-exempt	5,986,000	2,775,000	15,937,000	7,554,000
Federal funds sold, securities purchased under agreements to resell and interest-bearing deposits with banks	16,668,000	2,199,000	28,155,000	4,538,000
Total interest income	374,810,000	271,449,000	970,933,000	817,466,000
Interest expense:
Deposits	10,137,000	7,267,000	20,541,000	28,061,000
Federal funds purchased and securities sold under agreements to repurchase	1,506,000	259,000	2,556,000	933,000
Corporate and subordinated debentures	4,958,000	3,896,000	13,874,000	13,314,000
Other borrowings		41,000		44,000
Total interest expense	16,601,000	11,463,000	36,971,000	42,352,000
Net interest income	358,209,000	259,986,000	933,962,000	775,114,000
Provision (recovery) for credit losses	23,876,000	(38,903,000)	34,713,000	(156,116,000)
Net interest income after provision (recovery) for credit losses	334,333,000	298,889,000	899,249,000	931,230,000
Noninterest income:
Securities gains, net	30,000	64,000	30,000	100,000
Other income	7,142,000	6,933,000	20,220,000	17,645,000
Total noninterest income	77,178,000	87,010,000	251,560,000	262,315,000
Noninterest expense:
Salaries and employee benefits	139,554,000	136,969,000	414,264,000	414,709,000
Occupancy expense	22,490,000	23,135,000	67,089,000	69,310,000
Information services expense	20,714,000	18,061,000	59,854,000	55,928,000
OREO and loan related expense	532,000	1,527,000	291,000	2,769,000
Amortization of intangibles	7,837,000	8,543,000	25,178,000	26,675,000
Supplies, printing and postage expense	2,621,000	2,310,000	7,210,000	7,480,000
Professional fees	3,495,000	2,415,000	11,575,000	7,990,000
FDIC assessment and other regulatory charges	6,300,000	4,245,000	16,444,000	13,017,000
Advertising and marketing	2,170,000	2,185,000	6,219,000	5,584,000
Extinguishment of debt cost				11,706,000
Merger and branch consolidation related expense	13,679,000	17,618,000	29,345,000	60,598,000
Other expense	21,041,000	15,282,000	62,733,000	48,618,000
Total noninterest expense	240,433,000	232,290,000	700,202,000	724,384,000
Earnings:
Income before provision for income taxes	171,078,000	153,609,000	450,607,000	469,161,000
Provision for income taxes	38,035,000	30,821,000	98,060,000	100,464,000
Net income	$ 133,043,000	$ 122,788,000	$ 352,547,000	$ 368,697,000
Earnings per common share:
Basic (in dollars per share)	$ 1.76	$ 1.75	$ 4.75	$ 5.22
Diluted (in dollars per share)	$ 1.75	$ 1.74	$ 4.71	$ 5.19
Weighted average common shares outstanding:
Basic (in shares)	75,606	70,066	74,185	70,643
Diluted (in shares)	76,182	70,576	74,791	71,108
Fees on deposit accounts
Noninterest income:
Noninterest income	$ 31,188,000	$ 26,130,000	$ 93,748,000	$ 75,348,000
Mortgage banking income
Noninterest income:
Noninterest income	2,262,000	15,560,000	18,336,000	52,555,000
Trust and investment services income
Noninterest income:
Noninterest income	9,603,000	9,150,000	29,152,000	27,461,000
Correspondent banking and capital market income
Noninterest income:
Noninterest income	20,552,000	25,164,000	76,150,000	79,789,000
SBA income
Noninterest income:
Noninterest income	$ 6,401,000	$ 4,009,000	$ 13,924,000	$ 9,417,000