SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Company’s Reportable Operating Segment Results (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Net interest income	$ 719,203	$ 628,465	$ 650,126
Noninterest income (loss)	(615,970)	147,171	155,566
Total net revenue	103,233	775,636	805,692
Salaries and employee benefits	297,859	284,124	286,117
Occupancy expense, net	48,237	48,214	46,741
Furniture and equipment expense	21,518	22,047	20,741
Deposit insurance	20,219	23,938	29,986
Other operating expenses	177,230	179,220	179,476
TOTAL NONINTEREST EXPENSE	565,063	557,543	563,061
Income (loss) before provision for credit losses and income taxes	(461,830)	218,093	242,631
Provision for credit losses	65,824	46,785	42,028
Provision for (benefit from) income taxes	(130,101)	18,615	25,546
NET INCOME (LOSS)	(397,553)	152,693	175,057
Assets	24,540,877	26,876,049	27,345,674
Community and Commercial Banking
Segment Reporting Information [Line Items]
Net interest income	717,433	627,698	650,928
Noninterest income (loss)	(655,833)	109,701	120,567
Total net revenue	61,600	737,399	771,495
Salaries and employee benefits	279,232	265,610	268,300
Occupancy expense, net	46,307	46,373	46,712
Furniture and equipment expense	21,518	22,045	20,740
Deposit insurance	20,219	23,938	29,986
Other operating expenses	169,633	173,295	173,480
TOTAL NONINTEREST EXPENSE	536,909	531,261	539,218
Income (loss) before provision for credit losses and income taxes	(475,309)	206,138	232,277
Provision for credit losses	65,824	46,785	42,028
Provision for (benefit from) income taxes	(130,121)	18,530	25,451
NET INCOME (LOSS)	(411,012)	140,823	164,798
Assets	24,536,042	26,870,061	27,338,690
Other
Segment Reporting Information [Line Items]
Net interest income	1,770	767	(802)
Noninterest income (loss)	39,863	37,470	34,999
Total net revenue	41,633	38,237	34,197
Salaries and employee benefits	18,627	18,514	17,817
Occupancy expense, net	1,930	1,841	29
Furniture and equipment expense	0	2	1
Deposit insurance	0	0	0
Other operating expenses	7,597	5,925	5,996
TOTAL NONINTEREST EXPENSE	28,154	26,282	23,843
Income (loss) before provision for credit losses and income taxes	13,479	11,955	10,354
Provision for credit losses	0	0	0
Provision for (benefit from) income taxes	20	85	95
NET INCOME (LOSS)	13,459	11,870	10,259
Assets	$ 4,835	$ 5,988	$ 6,984