SUMMARY OF QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Quarterly Financial Information Disclosure [Abstract]
Net interest income	$ 156,137	$ 145,756	$ 147,132	$ 152,212	$ 165,220	$ 155,876	$ 142,461	$ 134,679	$ 601,237	$ 598,236	$ 560,560
Provision (benefit) for credit losses	11,738	1,516	5,379	3,074	3,387	5,492	3,246	3,245	21,707	15,370	(17,575)
NET INTEREST INCOME AFTER PROVISION FOR CREDIT LOSSES	144,399	144,240	141,753	149,138	161,833	150,384	139,215	131,434	579,530	582,866	578,135
Noninterest income	(111,801)	28,383	32,493	29,999	29,975	29,181	34,539	34,569	(20,926)	128,264	128,935
Noninterest expense	130,285	111,053	109,446	111,043	117,218	108,883	106,479	110,797	461,827	443,377	431,812
Income taxes	(27,324)	13,479	15,384	15,318	13,936	14,118	15,402	12,117	16,857	55,573	55,335
NET INCOME	(70,363)	48,091	49,416	52,776	60,654	56,564	51,873	43,089	79,920	212,180	219,923
Preferred dividends	(2,012)	(2,013)	(2,012)	(2,013)	(2,012)	(2,013)	(2,012)	(2,013)	(8,050)	(8,050)	(8,050)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS	$ (72,375)	$ 46,078	$ 47,404	$ 50,763	$ 58,642	$ 54,551	$ 49,861	$ 41,076	$ 71,870	$ 204,130	$ 211,873
Per share:
Earnings (loss) per share — basic (in dollars per share)	$ (1.69)	$ 1.08	$ 1.11	$ 1.19	$ 1.38	$ 1.28	$ 1.17	$ 0.97	$ 1.68	$ 4.80	$ 5.01
Earnings (loss) per share — diluted (in dollars per share)	(1.69)	1.08	1.11	1.19	1.37	1.28	1.17	0.97	1.68	4.79	5.00
Cash dividends declared on common stock (in dollars per share)	0.30	0.30	0.30	0.30	0.28	0.27	0.27	0.27	$ 1.20	$ 1.09	$ 0.96
Book value per common share (in dollars per share)	$ 42.69	$ 40.20	$ 41.00	$ 40.38	$ 38.25	$ 36.41	$ 39.19	$ 42.98
Weighted average common shares outstanding (in shares)	42,770,347	42,760,406	42,695,522	42,614,806	42,578,977	42,574,557	42,474,835	42,359,582	42,701,000	42,496,000	42,260,000
Weighted average diluted common shares outstanding (in shares)	42,838,405	42,812,563	42,757,603	42,742,878	42,699,752	42,643,940	42,565,391	42,540,953	42,792,000	42,631,000	42,411,000