GOODWILL AND IDENTIFIABLE INTANGIBLE ASSETS (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)
Identifiable Intangible Assets
Gross Carrying Amount	$ 196,636	$ 186,202
Accumulated Amortization	(132,396)	(120,976)
Net Carrying Amount	64,240	65,226
Estimated aggregate amortization expense for each of five succeeding fiscal years
Oct - Dec 2022	3,771
2023	13,567
2024	11,482
2025	9,783
2026	8,685
Thereafter	16,952
Net Carrying Amount	64,240	65,226
Components of goodwill
Goodwill, net, beginning of period	799,109
Goodwill, net, activity	45,875
Goodwill, net, end of period	844,984
Core deposit intangibles
Identifiable Intangible Assets
Gross Carrying Amount	77,373	69,403
Accumulated Amortization	(63,823)	(60,316)
Net Carrying Amount	13,550	9,087
Estimated aggregate amortization expense for each of five succeeding fiscal years
Net Carrying Amount	13,550	9,087
Other intangibles
Identifiable Intangible Assets
Gross Carrying Amount	119,263	116,799
Accumulated Amortization	(68,573)	(60,660)
Net Carrying Amount	50,690	56,139
Estimated aggregate amortization expense for each of five succeeding fiscal years
Net Carrying Amount	$ 50,690	$ 56,139