SUMMARY OF QUARTERLY FINANCIAL INFORMATION (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Quarterly Financial Information Disclosure [Abstract]
Net interest income	$ 165,220	$ 155,876	$ 142,461	$ 134,679	$ 137,194	$ 142,543	$ 141,218	$ 139,605	$ 598,236	$ 560,560	$ 491,729
Provision (benefit) for credit losses	3,387	5,492	3,246	3,245	(5,313)	(4,534)	(7,080)	(648)	15,370	(17,575)	67,066
NET INTEREST INCOME AFTER PROVISION FOR CREDIT LOSSES	161,833	150,384	139,215	131,434	142,507	147,077	148,298	140,253	582,866	578,135	424,663
Noninterest income	29,975	29,181	34,539	34,569	32,730	32,724	33,164	30,317	128,264	128,935	120,291
Noninterest expense	117,218	108,883	106,479	110,797	115,386	110,627	103,376	102,423	443,377	431,812	370,963
Income taxes	13,936	14,118	15,402	12,117	10,271	13,250	16,481	15,333	55,573	55,335	36,053
NET INCOME	60,654	56,564	51,873	43,089	49,580	55,924	61,605	52,814	212,180	219,923	137,938
Preferred dividends	(2,012)	(2,013)	(2,012)	(2,013)	(2,012)	(2,013)	(2,012)	(2,013)	(8,050)	(8,050)	(4,451)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS	$ 58,642	$ 54,551	$ 49,861	$ 41,076	$ 47,568	$ 53,911	$ 59,593	$ 50,801	$ 204,130	$ 211,873	$ 133,487
Per share:
Earnings per share — basic (in dollars per share)	$ 1.38	$ 1.28	$ 1.17	$ 0.97	$ 1.12	$ 1.27	$ 1.41	$ 1.20	$ 4.80	$ 5.01	$ 3.58
Earnings per share — diluted (in dollars per share)	1.37	1.28	1.17	0.97	1.12	1.27	1.41	1.20	4.79	5.00	3.57
Cash dividends declared on common stock (in dollars per share)	0.28	0.27	0.27	0.27	0.27	0.25	0.22	0.22	$ 1.09	$ 0.96	$ 0.80
Book value per common share (in dollars per share)	$ 38.25	$ 36.41	$ 39.19	$ 42.98	$ 49.00	$ 48.79	$ 48.50	$ 46.13
Weighted average common shares outstanding (in shares)	42,578,977	42,574,557	42,474,835	42,359,582	42,309,003	42,302,780	42,242,893	42,174,092	42,496,000	42,260,000	37,269,000
Weighted average diluted common shares outstanding (in shares)	42,699,752	42,643,940	42,565,391	42,540,953	42,479,442	42,415,993	42,359,873	42,335,747	42,631,000	42,411,000	37,357,000