Business Segments - Financial Information by Business Segment (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Segment Reporting Information [Line Items]
Interest and dividend income	$ 160,555	$ 112,174
Interest expense	36,223	4,463
NET INTEREST INCOME	124,332	107,711
Provision for credit losses	3,577	(3,438)
Net interest income after provision for credit losses	120,755	111,149
Non-interest income	27,653	30,382
Non-interest expense	96,125	87,548
Income before provision for income taxes	52,283	53,983
Provision for income taxes	9,942	9,859
Net income	42,341	44,124
Preferred stock dividends	2,531	2,531
Net income available to common shareholders	39,810	41,593
Community Banking [Member]
Segment Reporting Information [Line Items]
Interest and dividend income	160,555	112,174
Interest expense	36,223	4,463
NET INTEREST INCOME	124,332	107,711
Provision for credit losses	3,577	(3,438)
Net interest income after provision for credit losses	120,755	111,149
Non-interest income	20,159	22,547
Non-interest expense	91,617	83,225
Income before provision for income taxes	49,297	50,471
Provision for income taxes	9,315	9,121
Net income	39,982	41,350
Preferred stock dividends	2,531	2,531
Net income available to common shareholders	37,451	38,819
Trust and Investment Services [Member]
Segment Reporting Information [Line Items]
Non-interest income	7,494	7,835
Non-interest expense	4,508	4,323
Income before provision for income taxes	2,986	3,512
Provision for income taxes	627	738
Net income	2,359	2,774
Net income available to common shareholders	$ 2,359	$ 2,774