LOANS AND LEASES - Commercial and Consumer Credit Exposure by Risk Attribute (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	$ 2,183,121
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,341,041
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	1,443,127
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	1,061,354
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	764,432
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	1,165,115
Financing Receivable, before Allowance for Credit Loss	8,958,190
Financing Receivable, Revolving	1,242,619
Loans and Leases Receivable, Net of Deferred Income	10,200,809	$ 9,201,665
Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		2,465,877
Commercial \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		2,324,021
Commercial \| Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		100,954
Commercial \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		40,902
Commercial \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		0
Construction real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		493,182
Construction real estate \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		493,182
Construction real estate \| Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		0
Construction real estate \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		0
Construction real estate \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		0
Commercial Real Estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		4,194,651
Commercial Real Estate \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		4,108,752
Commercial Real Estate \| Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		59,383
Commercial Real Estate \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		26,516
Commercial Real Estate \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		0
Lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		88,364
Lease financing \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		85,262
Lease financing \| Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		488
Lease financing \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		2,614
Lease financing \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		0
Commercial segment
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		7,242,074
Commercial segment \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		7,011,217
Commercial segment \| Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		160,825
Commercial segment \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		70,032
Commercial segment \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		0
Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		1,055,949
Residential real estate \| Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		1,040,787
Residential real estate \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		15,162
Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		771,869
Home equity \| Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		766,169
Home equity \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		5,700
Installment
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		82,589
Installment \| Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		82,385
Installment \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		204
Credit card
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		49,184
Credit card \| Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		48,983
Credit card \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		201
Total consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		1,959,591
Total consumer \| Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		1,938,324
Total consumer \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Net of Deferred Income		21,267
Commercial segment
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	1,280,855
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	510,205
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	408,244
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	281,523
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	162,581
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	162,841
Financing Receivable, before Allowance for Credit Loss	2,806,249
Financing Receivable, Revolving	486,064
Loans and Leases Receivable, Net of Deferred Income	3,292,313	2,465,877
Commercial segment \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	1,254,361
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	502,248
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	384,079
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	242,588
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	153,411
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	152,890
Financing Receivable, before Allowance for Credit Loss	2,689,577
Financing Receivable, Revolving	468,883
Loans and Leases Receivable, Net of Deferred Income	3,158,460
Commercial segment \| Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	21,981
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	6,871
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	16,363
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	13,925
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	2,366
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	8,325
Financing Receivable, before Allowance for Credit Loss	69,831
Financing Receivable, Revolving	10,570
Loans and Leases Receivable, Net of Deferred Income	80,401
Commercial segment \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	4,513
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,086
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	7,802
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	25,010
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	6,804
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	1,626
Financing Receivable, before Allowance for Credit Loss	46,841
Financing Receivable, Revolving	6,611
Loans and Leases Receivable, Net of Deferred Income	53,452
Commercial segment \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, before Allowance for Credit Loss	0
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	0
Lease financing
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	11,410
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	30,564
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	14,348
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	8,805
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	6,248
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	3,367
Financing Receivable, before Allowance for Credit Loss	74,742
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	74,742	88,364
Lease financing \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	11,084
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	30,564
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	13,872
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	7,983
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	5,971
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	3,367
Financing Receivable, before Allowance for Credit Loss	72,841
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	72,841
Lease financing \| Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	317
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, before Allowance for Credit Loss	317
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	317
Lease financing \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	9
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	476
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	822
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	277
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, before Allowance for Credit Loss	1,584
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	1,584
Lease financing \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, before Allowance for Credit Loss	0
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	0
Construction real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	53,598
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	212,583
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	223,732
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	44,936
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	23,987
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	990
Financing Receivable, before Allowance for Credit Loss	559,826
Financing Receivable, Revolving	15,822
Loans and Leases Receivable, Net of Deferred Income	575,648	493,182
Construction real estate \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	53,598
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	211,962
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	223,732
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	34,952
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	23,987
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	990
Financing Receivable, before Allowance for Credit Loss	549,221
Financing Receivable, Revolving	15,822
Loans and Leases Receivable, Net of Deferred Income	565,043
Construction real estate \| Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	621
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	9,984
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, before Allowance for Credit Loss	10,605
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	10,605
Construction real estate \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, before Allowance for Credit Loss	0
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	0
Construction real estate \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, before Allowance for Credit Loss	0
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	0
Commercial real estate - investor
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	386,870
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,098,843
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	463,362
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	473,514
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	344,531
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	456,064
Financing Receivable, before Allowance for Credit Loss	3,223,184
Financing Receivable, Revolving	40,029
Loans and Leases Receivable, Net of Deferred Income	3,263,213
Commercial real estate - investor \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	379,720
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,096,225
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	445,501
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	451,095
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	327,564
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	431,524
Financing Receivable, before Allowance for Credit Loss	3,131,629
Financing Receivable, Revolving	39,470
Loans and Leases Receivable, Net of Deferred Income	3,171,099
Commercial real estate - investor \| Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	952
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	56
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	15,178
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	16,873
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	8,697
Financing Receivable, before Allowance for Credit Loss	41,756
Financing Receivable, Revolving	559
Loans and Leases Receivable, Net of Deferred Income	42,315
Commercial real estate - investor \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	6,198
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	2,562
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	17,861
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	7,241
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	94
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	15,843
Financing Receivable, before Allowance for Credit Loss	49,799
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	49,799
Commercial real estate - investor \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, before Allowance for Credit Loss	0
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	0
Commercial real estate-owner
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	158,181
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	183,274
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	166,937
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	154,411
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	145,552
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	234,957
Financing Receivable, before Allowance for Credit Loss	1,043,312
Financing Receivable, Revolving	40,600
Loans and Leases Receivable, Net of Deferred Income	1,083,912
Commercial real estate-owner \| Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	155,486
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	180,808
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	153,043
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	144,601
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	140,566
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	219,723
Financing Receivable, before Allowance for Credit Loss	994,227
Financing Receivable, Revolving	40,541
Loans and Leases Receivable, Net of Deferred Income	1,034,768
Commercial real estate-owner \| Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	2,048
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	1,946
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	13,043
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	4,903
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	4,540
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	11,873
Financing Receivable, before Allowance for Credit Loss	38,353
Financing Receivable, Revolving	59
Loans and Leases Receivable, Net of Deferred Income	38,412
Commercial real estate-owner \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	647
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	520
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	851
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	4,907
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	446
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	3,361
Financing Receivable, before Allowance for Credit Loss	10,732
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	10,732
Commercial real estate-owner \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	0
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	0
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	0
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	0
Financing Receivable, before Allowance for Credit Loss	0
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	0
Residential real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	228,291
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	265,549
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	134,204
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	75,320
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	68,197
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	256,141
Financing Receivable, before Allowance for Credit Loss	1,027,702
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	1,027,702	1,055,949
Residential real estate \| Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	228,049
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	265,023
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	133,562
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	74,811
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	68,109
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	250,625
Financing Receivable, before Allowance for Credit Loss	1,020,179
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	1,020,179
Residential real estate \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	242
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	526
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	642
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	509
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	88
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	5,516
Financing Receivable, before Allowance for Credit Loss	7,523
Financing Receivable, Revolving	0
Loans and Leases Receivable, Net of Deferred Income	7,523
Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	45,297
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	22,107
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	19,466
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	12,457
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	10,733
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	47,043
Financing Receivable, before Allowance for Credit Loss	157,103
Financing Receivable, Revolving	597,640
Loans and Leases Receivable, Net of Deferred Income	754,743	771,869
Home equity \| Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	45,297
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	22,107
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	19,391
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	12,418
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	10,704
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	46,839
Financing Receivable, before Allowance for Credit Loss	156,756
Financing Receivable, Revolving	594,615
Loans and Leases Receivable, Net of Deferred Income	751,371
Home equity \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	0
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	0
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	75
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	39
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	29
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	204
Financing Receivable, before Allowance for Credit Loss	347
Financing Receivable, Revolving	3,025
Loans and Leases Receivable, Net of Deferred Income	3,372
Total consumer
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	18,619
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	17,916
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	12,834
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	10,388
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	2,603
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	3,712
Financing Receivable, before Allowance for Credit Loss	66,072
Financing Receivable, Revolving	18,557
Loans and Leases Receivable, Net of Deferred Income	84,629	82,589
Total consumer \| Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	18,610
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	17,887
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	12,809
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	10,367
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	2,582
Financing Receivable, Originated, More than Five Years before Current Fiscal Year	3,708
Financing Receivable, before Allowance for Credit Loss	65,963
Financing Receivable, Revolving	18,557
Loans and Leases Receivable, Net of Deferred Income	84,520
Total consumer \| Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Year One, Originated, Current Fiscal Year	9
Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year	29
Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year	25
Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year	21
Financing Receivable, Year Five, Originated, Four Years before Current Fiscal Year	21

LOANS AND LEASES - Commercial and Consumer Credit Exposure by Risk Attribute (Details) - USD ($)
$ in Thousands

Sep. 30, 2020

Dec. 31, 2019

Financing Receivable, Credit Quality Indicator [Line Items]

Financing Receivable, Year One, Originated, Current Fiscal Year

$ 2,183,121

Financing Receivable, Year Two, Originated, Fiscal Year before Current Fiscal Year

2,341,041

Financing Receivable, Year Three, Originated, Two Years before Current Fiscal Year

1,443,127

Financing Receivable, Year Four, Originated, Three Years before Current Fiscal Year

1,061,354