GOODWILL AND OTHER INTANGIBLE ASSETS - Amount of Goodwill by Reportable Segment (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2022 USD ($)
Goodwill [Roll Forward]
Beginning balance	$ 370,223
Disposal of subsidiary's assets	(6,787)
Ending balance	363,436
Community Banking
Goodwill [Roll Forward]
Beginning balance	331,689
Disposal of subsidiary's assets	0
Ending balance	331,689
Insurance
Goodwill [Roll Forward]
Beginning balance	6,787
Disposal of subsidiary's assets	(6,787)
Ending balance	0
Investment Management
Goodwill [Roll Forward]
Beginning balance	31,747
Disposal of subsidiary's assets	0
Ending balance	$ 31,747