BUSINESS COMBINATIONS - Corporate Development and Restructuring Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Business Acquisition [Line Items]
Salaries, benefits and other compensation	$ 72,294	$ 53,344	$ 211,413	$ 158,890
Occupancy expense	9,699	8,150	30,393	24,693
Equipment expense	9,913	6,807	30,674	21,536
Professional fees	3,561	4,244	12,285	11,501
Data processing and operations expenses	5,362	3,467	16,009	10,296
Marketing expense	2,082	1,480	4,985	3,758
Total corporate development and restructuring expenses	132,917	$ 96,446	441,423	$ 288,097
Bryn Mawr Bank Corporation Acquisition
Business Acquisition [Line Items]
Salaries, benefits and other compensation	112		12,370
Occupancy expense	(2,211)		9,149
Equipment expense	1,278		20,969
Professional fees	899		12,781
Data processing and operations expenses	1		100
Marketing expense	41		3,014
Other operating expense, net	2,472		6,088
Total corporate development and restructuring expenses	$ 2,592		$ 64,471