Consolidated Statements of Income - USD ($) shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Interest income:
Loans, including fees	$ 419,355,000	$ 272,000,000	$ 812,720,000	$ 505,617,000
Investment securities:
Taxable	41,254,000	38,948,000	82,819,000	69,068,000
Tax-exempt	5,586,000	6,076,000	12,144,000	9,951,000
Federal funds sold, securities purchased under agreements to resell and interest-bearing deposits with banks	11,858,000	9,309,000	20,779,000	12,168,000
Total interest income	478,053,000	326,333,000	928,462,000	596,804,000
Interest expense:
Deposits	100,787,000	4,914,000	156,729,000	9,506,000
Federal funds purchased and securities sold under agreements to repurchase	3,535,000	781,000	6,388,000	1,050,000
Corporate and subordinated debentures	5,823,000	4,823,000	11,558,000	8,916,000
Other borrowings	6,165,000		10,781,000
Total interest expense	116,310,000	10,518,000	185,456,000	19,472,000
Net interest income	361,743,000	315,815,000	743,006,000	577,332,000
Provision for credit losses	38,389,000	19,286,000	71,480,000	10,837,000
Net interest income after provision for credit losses	323,354,000	296,529,000	671,526,000	566,495,000
Noninterest income:
Securities gains, net		0	45,000	0
Other income	7,864,000	8,172,000	17,730,000	14,766,000
Total noninterest income	77,214,000	86,756,000	148,569,000	172,803,000
Noninterest expense:
Salaries and employee benefits	147,342,000	137,037,000	291,402,000	274,710,000
Occupancy expense	22,196,000	22,759,000	43,729,000	44,599,000
Information services expense	21,119,000	19,947,000	41,044,000	39,140,000
OREO and loan related expense (recovery)	(14,000)	(3,000)	155,000	(241,000)
Amortization of intangibles	7,028,000	8,847,000	14,327,000	17,341,000
Supplies, printing and postage expense	2,554,000	2,400,000	5,194,000	4,589,000
Professional fees	4,364,000	4,331,000	8,066,000	8,080,000
FDIC assessment and other regulatory charges	9,819,000	5,332,000	16,113,000	10,144,000
Advertising and marketing	1,521,000	2,286,000	3,639,000	4,049,000
Merger, branch consolidation and severance related expense	1,808,000	5,390,000	11,220,000	15,666,000
Other expense	24,889,000	22,843,000	48,242,000	41,692,000
Total noninterest expense	242,626,000	231,169,000	483,131,000	459,769,000
Earnings:
Income before provision for income taxes	157,942,000	152,116,000	336,964,000	279,529,000
Provision for income taxes	34,495,000	32,941,000	73,591,000	60,025,000
Net income	$ 123,447,000	$ 119,175,000	$ 263,373,000	$ 219,504,000
Earnings per common share:
Basic (in dollars per share)	$ 1.62	$ 1.58	$ 3.47	$ 2.99
Diluted (in dollars per share)	$ 1.62	$ 1.57	$ 3.45	$ 2.96
Weighted average common shares outstanding:
Basic (in shares)	76,058	75,461	75,981	73,465
Diluted (in shares)	76,418	76,094	76,394	74,104
Fees on deposit accounts
Noninterest income:
Noninterest income	$ 33,101,000	$ 32,862,000	$ 62,960,000	$ 60,871,000
Mortgage banking income
Noninterest income:
Noninterest income	4,354,000	5,480,000	8,686,000	16,074,000
Trust and investment services income
Noninterest income:
Noninterest income	9,823,000	9,831,000	19,760,000	19,549,000
Correspondent banking and capital market income
Noninterest income:
Noninterest income	19,187,000	26,068,000	32,781,000	54,019,000
SBA income
Noninterest income:
Noninterest income	$ 2,885,000	$ 4,343,000	$ 6,607,000	$ 7,524,000