COMMITMENTS AND CONTINGENCIES - Loan and Unfunded Commitments (Details) - USD ($) $ in Thousands	Sep. 30, 2026	Dec. 31, 2025
Other Commitments [Line Items]
Unused Commitments to Extend Credit	$ 4,812,069	$ 4,467,728
Gross loans and leases, excluding accrued interest	13,905,082	13,424,070
Commercial
Other Commitments [Line Items]
Unused Commitments to Extend Credit	2,233,733	2,066,620
Gross loans and leases, excluding accrued interest	4,948,380	4,632,241
Lease financing
Other Commitments [Line Items]
Unused Commitments to Extend Credit	13,963	0
Gross loans and leases, excluding accrued interest	678,423	638,527
Construction real estate
Other Commitments [Line Items]
Unused Commitments to Extend Credit	706,294	680,920
Gross loans and leases, excluding accrued interest	606,696	677,339
Commercial real estate - investor
Other Commitments [Line Items]
Unused Commitments to Extend Credit	182,054	204,747
Gross loans and leases, excluding accrued interest	3,400,040	3,246,889
Commercial real estate-owner
Other Commitments [Line Items]
Unused Commitments to Extend Credit	48,364	39,973
Gross loans and leases, excluding accrued interest	1,142,528	1,137,667
Residential real estate
Other Commitments [Line Items]
Unused Commitments to Extend Credit	0	0
Gross loans and leases, excluding accrued interest	1,806,123	1,832,184
Home equity
Other Commitments [Line Items]
Unused Commitments to Extend Credit	1,199,185	1,103,581
Gross loans and leases, excluding accrued interest	1,105,790	1,005,204
Installment
Other Commitments [Line Items]
Unused Commitments to Extend Credit	70,272	48,606
Gross loans and leases, excluding accrued interest	150,485	188,694
Credit card
Other Commitments [Line Items]
Unused Commitments to Extend Credit	358,204	323,281
Gross loans and leases, excluding accrued interest	$ 66,617	$ 65,325