LOANS AND LEASES - Loan Delinquency, including Nonaccrual Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 24,924	$ 48,554
Current	10,175,885	9,084,447
Loans and Leases Receivable, Gross		9,133,001
Purchased impaired loans		68,664
Total loans and leases	10,200,809	9,201,665
> 90 days past due and still accruing	79	201
Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	5,442	12,923
Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	8,890	7,325
Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	10,592	28,306
Commercial
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	2,368	19,116
Current	3,289,945	2,443,680
Loans and Leases Receivable, Gross		2,462,796
Purchased impaired loans		3,081
Total loans and leases	3,292,313	2,465,877
> 90 days past due and still accruing	0	0
Commercial | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	54	1,266
Commercial | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	133	3,332
Commercial | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	2,181	14,518
Lease financing
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Current	74,742	88,364
Loans and Leases Receivable, Gross		88,364
Purchased impaired loans		0
Total loans and leases	74,742	88,364
> 90 days past due and still accruing	0	0
Lease financing | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Lease financing | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Lease financing | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Construction real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Current	575,648	493,167
Loans and Leases Receivable, Gross		493,167
Purchased impaired loans		15
Total loans and leases	575,648	493,182
> 90 days past due and still accruing	0	0
Construction real estate | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Construction real estate | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Construction real estate | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0	0
Commercial real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due		7,246
Current		4,151,513
Loans and Leases Receivable, Gross		4,158,759
Purchased impaired loans		35,892
Total loans and leases	4,347,125	4,194,651
> 90 days past due and still accruing		0
Commercial real estate | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due		776
Commercial real estate | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due		857
Commercial real estate | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due		5,613
Commercial real estate - investor
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	9,265
Current	3,253,948
Total loans and leases	3,263,213
> 90 days past due and still accruing	0
Commercial real estate - investor | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	84
Commercial real estate - investor | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	7,895
Commercial real estate - investor | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,286
Commercial real estate-owner
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,806
Current	1,082,106
Total loans and leases	1,083,912
> 90 days past due and still accruing	0
Commercial real estate-owner | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	755
Commercial real estate-owner | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	0
Commercial real estate-owner | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,051
Residential real estate
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	7,524	14,991
Current	1,020,178	1,014,138
Loans and Leases Receivable, Gross		1,029,129
Purchased impaired loans		26,820
Total loans and leases	1,027,702	1,055,949
> 90 days past due and still accruing	0	0
Residential real estate | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	2,816	8,032
Residential real estate | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	340	1,928
Residential real estate | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	4,368	5,031
Home equity
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	3,372	6,408
Current	751,371	762,863
Loans and Leases Receivable, Gross		769,271
Purchased impaired loans		2,598
Total loans and leases	754,743	771,869
> 90 days past due and still accruing	0	0
Home equity | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,468	2,530
Home equity | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	319	1,083
Home equity | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	1,585	2,795
Installment
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	108	309
Current	84,521	82,022
Loans and Leases Receivable, Gross		82,331
Purchased impaired loans		258
Total loans and leases	84,629	82,589
> 90 days past due and still accruing	0	0
Installment | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	50	111
Installment | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	20	50
Installment | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	38	148
Credit card
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	481	484
Current	43,426	48,700
Loans and Leases Receivable, Gross		49,184
Purchased impaired loans		0
Total loans and leases	43,907	49,184
> 90 days past due and still accruing	79	201
Credit card | Financial Asset, 30 to 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	215	208
Credit card | Financial Asset, 60 to 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	183	75
Credit card | Financial Asset, Equal to or Greater than 90 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Past Due	$ 83	$ 201