ALLOWANCE FOR CREDIT LOSSES AND CREDIT QUALITY INFORMATION - Schedule of Allowance for Loan Losses and Loan Balances (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Allowance for credit losses
Beginning balance	$ 136,330	$ 204,818	$ 94,507	$ 228,804
Initial allowance on acquired PCD loans			26,103
Charge-offs	(3,967)	(7,078)	(8,818)	(12,554)
Recoveries	1,339	2,241	2,939	3,891
(Credit) provision	8,268	(67,563)	27,239	(87,723)
Ending balance	141,970	132,418	141,970	132,418
Period-end allowance allocated to:
Loans evaluated on an individual basis	5,437	11	5,437	11
Loans evaluated on a collective basis	136,533	132,407	136,533	132,407
Period-end loan balances:
Loans evaluated on an individual basis	50,795	29,950	50,795	29,950
Loans evaluated on a collective basis	11,429,323	8,225,940	11,429,323	8,225,940
Gross loans	11,480,118	8,255,890	11,480,118	8,255,890	$ 7,882,055
Reverse mortgage, fair value	2,600	8,400	2,600	8,400	3,900
Bryn Mawr Bank Corporation Acquisition
Allowance for credit losses
Initial allowance on acquired PCD loans			26,100
Period-end loan balances:
Loans purchased with no credit deterioration			23,500
Commercial | Commercial and industrial
Allowance for credit losses
Beginning balance	65,716	125,870	49,967	150,875
Initial allowance on acquired PCD loans			22,614
Charge-offs	(2,549)	(6,512)	(6,188)	(11,564)
Recoveries	870	1,379	1,471	2,519
(Credit) provision	(3,116)	(33,534)	(6,943)	(54,627)
Ending balance	60,921	87,203	60,921	87,203
Period-end allowance allocated to:
Loans evaluated on an individual basis	5,437	1	5,437	1
Loans evaluated on a collective basis	55,484	87,202	55,484	87,202
Period-end loan balances:
Loans evaluated on an individual basis	29,030	14,446	29,030	14,446
Loans evaluated on a collective basis	3,078,710	2,365,251	3,078,710	2,365,251
Gross loans	3,107,740	2,379,697	3,107,740	2,379,697	2,270,319
Commercial | Owner-occupied commercial
Allowance for credit losses
Beginning balance	6,125	9,617	4,574	9,615
Initial allowance on acquired PCD loans			595
Charge-offs	0	(45)	(179)	(45)
Recoveries	141	15	267	105
(Credit) provision	(756)	(3,406)	253	(3,494)
Ending balance	5,510	6,181	5,510	6,181
Period-end allowance allocated to:
Loans evaluated on an individual basis	0	0	0	0
Loans evaluated on a collective basis	5,510	6,181	5,510	6,181
Period-end loan balances:
Loans evaluated on an individual basis	787	3,868	787	3,868
Loans evaluated on a collective basis	1,822,442	1,356,813	1,822,442	1,356,813
Gross loans	1,823,229	1,360,681	1,823,229	1,360,681	1,341,707
Commercial | Commercial mortgages
Allowance for credit losses
Beginning balance	23,105	30,545	11,623	31,071
Initial allowance on acquired PCD loans			2,684
Charge-offs	0	0	(37)	0
Recoveries	1	30	122	44
(Credit) provision	557	(14,476)	9,271	(15,016)
Ending balance	23,663	16,099	23,663	16,099
Period-end allowance allocated to:
Loans evaluated on an individual basis	0	10	0	10
Loans evaluated on a collective basis	23,663	16,089	23,663	16,089
Period-end loan balances:
Loans evaluated on an individual basis	7,771	3,962	7,771	3,962
Loans evaluated on a collective basis	3,313,883	2,020,722	3,313,883	2,020,722
Gross loans	3,321,654	2,024,684	3,321,654	2,024,684	1,881,510
Commercial | Construction
Allowance for credit losses
Beginning balance	3,145	14,287	1,903	12,190
Initial allowance on acquired PCD loans			71
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
(Credit) provision	1,913	(10,775)	3,084	(8,678)
Ending balance	5,058	3,512	5,058	3,512
Period-end allowance allocated to:
Loans evaluated on an individual basis	0	0	0	0
Loans evaluated on a collective basis	5,058	3,512	5,058	3,512
Period-end loan balances:
Loans evaluated on an individual basis	5,392	72	5,392	72
Loans evaluated on a collective basis	928,932	779,529	928,932	779,529
Gross loans	934,324	779,601	934,324	779,601	687,213
Residential
Allowance for credit losses
Beginning balance	4,956	5,702	3,352	6,893
Initial allowance on acquired PCD loans			61
Charge-offs	0	0	(186)	0
Recoveries	144	455	530	595
(Credit) provision	(112)	(2,864)	1,231	(4,195)
Ending balance	4,988	3,293	4,988	3,293
Period-end allowance allocated to:
Loans evaluated on an individual basis	0	0	0	0
Loans evaluated on a collective basis	4,988	3,293	4,988	3,293
Period-end loan balances:
Loans evaluated on an individual basis	5,803	4,994	5,803	4,994
Loans evaluated on a collective basis	764,772	601,064	764,772	601,064
Gross loans	770,575	606,058	770,575	606,058	542,733
Consumer
Allowance for credit losses
Beginning balance	33,283	18,797	23,088	18,160
Initial allowance on acquired PCD loans			78
Charge-offs	(1,418)	(521)	(2,228)	(945)
Recoveries	183	362	549	628
(Credit) provision	9,782	(2,508)	20,343	(1,713)
Ending balance	41,830	16,130	41,830	16,130
Period-end allowance allocated to:
Loans evaluated on an individual basis	0	0	0	0
Loans evaluated on a collective basis	41,830	16,130	41,830	16,130
Period-end loan balances:
Loans evaluated on an individual basis	2,012	2,608	2,012	2,608
Loans evaluated on a collective basis	1,520,584	1,102,561	1,520,584	1,102,561
Gross loans	$ 1,522,596	$ 1,105,169	$ 1,522,596	$ 1,105,169	$ 1,158,573