OPERATING SEGMENTS AND RELATED INFORMATION - Schedule of Goodwill and Total Assets of Segments (Details) - USD ($) $ in Thousands	Dec. 31, 2025	Dec. 31, 2024
Segment Reporting Information [Line Items]
Goodwill	$ 383,280	$ 333,695
Total assets	18,104,736	12,046,722
Banking
Segment Reporting Information [Line Items]
Goodwill	360,180	310,595
Wealth Management
Segment Reporting Information [Line Items]
Goodwill	14,108	14,108
FirsTech
Segment Reporting Information [Line Items]
Goodwill	8,992	8,992
Operating Segments | Banking
Segment Reporting Information [Line Items]
Goodwill	360,180	310,595
Total assets	17,880,797	11,856,651
Operating Segments | Wealth Management
Segment Reporting Information [Line Items]
Goodwill	14,108	14,108
Total assets	152,422	126,180
Operating Segments | FirsTech
Segment Reporting Information [Line Items]
Goodwill	8,992	8,992
Total assets	45,373	57,737
Other
Segment Reporting Information [Line Items]
Goodwill	0	0
Total assets	$ 26,144	$ 6,154