PARENT COMPANY ONLY FINANCIAL INFORMATION (Income Statements) (Details) - USD ($) $ 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
Operating expenses:
Interest									$ 352,559	$ 76,420	$ 28,200
Salaries and employee benefits									251,276	254,478	240,114
Professional fees									58,667	58,606	58,843
INCOME BEFORE INCOME TAXES									96,777	267,753	275,258
Income tax benefit	$ 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
Parent
Operating revenues:
Dividends from subsidiaries									50,000	142,500	163,500
Other									1,486	1,200	1,885
Total operating revenues									51,486	143,700	165,385
Operating expenses:
Interest									22,637	16,886	12,851
Salaries and employee benefits									4,610	7,225	7,509
Professional fees									8,807	11,594	5,161
Other operating expenses									9,287	10,474	10,984
Total operating expenses									45,341	46,179	36,505
Equity in undistributed earnings									57,799	98,983	75,368
INCOME BEFORE INCOME TAXES									63,944	196,504	204,248
Income tax benefit									15,976	15,676	15,675
NET INCOME									79,920	212,180	219,923
Preferred dividends									(8,050)	(8,050)	(8,050)
NET INCOME AVAILABLE TO COMMON STOCKHOLDERS									$ 71,870	$ 204,130	$ 211,873