PARENT COMPANY ONLY FINANCIAL INFORMATION (Income Statements) (Details) - USD ($) $ 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
Operating expenses:
Interest									$ 76,420	$ 28,200	$ 44,883
Salaries and employee benefits									254,478	240,114	202,668
Professional fees									65,606	64,600	54,068
INCOME BEFORE INCOME TAXES									267,753	275,258	173,991
Income tax benefit	$ (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
Parent
Operating revenues:
Dividends from subsidiaries									142,500	163,500	83,000
Other									1,200	1,885	1,948
Total operating revenues									143,700	165,385	84,948
Operating expenses:
Interest									16,886	12,851	13,573
Salaries and employee benefits									7,225	7,509	8,147
Professional fees									11,594	5,161	4,310
Other operating expenses									10,474	10,984	4,939
Total operating expenses									46,179	36,505	30,969
Equity in undistributed earnings									98,983	75,368	73,430
INCOME BEFORE INCOME TAXES									196,504	204,248	127,409
Income tax benefit									15,676	15,675	10,529
NET INCOME									212,180	219,923	137,938
Preferred dividends									(8,050)	(8,050)	(4,451)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS									$ 204,130	$ 211,873	$ 133,487