Condensed Consolidated Statements of Net Income - USD ($) shares in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Interest income:
Loans, including fees	$ 393,366,000	$ 233,617,000
Investment securities:
Taxable	41,565,000	30,120,000
Tax-exempt	6,557,000	3,875,000
Federal funds sold, securities purchased under agreements to resell and interest-bearing deposits with banks	8,921,000	2,859,000
Total interest income	450,409,000	270,471,000
Interest expense:
Deposits	55,942,000	4,591,000
Federal funds purchased and securities sold under agreements to repurchase	2,853,000	269,000
Corporate and subordinated debentures	5,735,000	4,093,000
Other borrowings	4,616,000
Total interest expense	69,146,000	8,953,000
Net interest income	381,263,000	261,518,000
Provision (recovery) for credit losses	33,091,000	(8,449,000)
Net interest income after provision (recovery) for credit losses	348,172,000	269,967,000
Noninterest income:
Securities gains, net	45,000
Other income	9,866,000	6,595,000
Total noninterest income	71,355,000	86,046,000
Noninterest expense:
Salaries and employee benefits	144,060,000	137,673,000
Occupancy expense	21,533,000	21,840,000
Information services expense	19,925,000	19,193,000
OREO and loan related expense (recovery)	169,000	(238,000)
Amortization of intangibles	7,299,000	8,494,000
Supplies, printing and postage expense	2,640,000	2,189,000
Professional fees	3,702,000	3,749,000
FDIC assessment and other regulatory charges	6,294,000	4,812,000
Advertising and marketing	2,118,000	1,763,000
Merger, branch consolidation and severance related expense	9,412,000	10,276,000
Other expense	23,353,000	18,849,000
Total noninterest expense	240,505,000	228,600,000
Earnings:
Income before provision for income taxes	179,022,000	127,413,000
Provision for income taxes	39,096,000	27,084,000
Net income	$ 139,926,000	$ 100,329,000
Earnings per common share:
Basic (in dollars per share)	$ 1.84	$ 1.40
Diluted (in dollars per share)	$ 1.83	$ 1.39
Weighted average common shares outstanding:
Basic (in shares)	75,902	71,447
Diluted (in shares)	76,389	72,111
Fees on deposit accounts
Noninterest income:
Noninterest income	$ 29,859,000	$ 28,009,000
Mortgage banking income
Noninterest income:
Noninterest income	4,332,000	10,594,000
Trust and investment services income
Noninterest income:
Noninterest income	9,937,000	9,718,000
Correspondent banking and capital market income
Noninterest income:
Noninterest income	13,594,000	27,950,000
SBA income
Noninterest income:
Noninterest income	$ 3,722,000	$ 3,180,000