OPERATING SEGMENTS AND RELATED INFORMATION - Schedule of Goodwill and Total Assets of Segments (Details) - USD ($) $ in Thousands	Mar. 31, 2025	Dec. 31, 2024
Segment Reporting Information [Line Items]
Goodwill	$ 385,139	$ 333,695
Total assets	19,464,252	12,046,722
Operating Segments | Banking
Segment Reporting Information [Line Items]
Goodwill	362,039	310,595
Total assets	19,271,919	11,856,651
Operating Segments | Wealth Management
Segment Reporting Information [Line Items]
Goodwill	14,108	14,108
Total assets	130,700	126,180
Operating Segments | FirsTech
Segment Reporting Information [Line Items]
Goodwill	8,992	8,992
Total assets	46,188	57,737
Other
Segment Reporting Information [Line Items]
Goodwill	0	0
Total assets	$ 15,445	$ 6,154