LOANS - Schedule of Industry and Rate Sensitivity (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	$ 2,150,263	$ 2,144,850
Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	2,150,263	2,144,850
Computer Programming, Data Processing & Other Computer Related Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	391,559	394,193
Computer Programming, Data Processing & Other Computer Related Services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Computer Programming, Data Processing & Other Computer Related Services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	14,868	15,002
Management & Public Relations Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	288,586	339,179
Management & Public Relations Services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt		0
Management & Public Relations Services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	145,446	0
Chemical & Chemical Preparations
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	145,446	0
Chemical & Chemical Preparations | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Chemical & Chemical Preparations | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	29,323	47,249
Miscellaneous Business Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	122,275	164,033
Miscellaneous Business Services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Miscellaneous Business Services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	391,559	394,193
Public Warehousing & Storage
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	119,577	107,029
Public Warehousing & Storage | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Public Warehousing & Storage | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	15,881	15,923
Engineering, Architectural, and Surveying
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	113,496	124,201
Engineering, Architectural, and Surveying | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Engineering, Architectural, and Surveying | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	44,442	43,175
Metal Cans & Shipping Containers
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	108,266	118,456
Metal Cans & Shipping Containers | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Metal Cans & Shipping Containers | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	23,266	24,000
Offices & Clinics of Doctors of Medicine
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	104,919	106,993
Offices & Clinics of Doctors of Medicine | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Offices & Clinics of Doctors of Medicine | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	113,496	124,201
Surgical, Medical & Dental Instruments & Supplies
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	100,791	102,182
Surgical, Medical & Dental Instruments & Supplies | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Surgical, Medical & Dental Instruments & Supplies | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	22,987	23,248
Home Health Care Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	74,013	75,410
Home Health Care Services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Home Health Care Services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	28,537	29,361
Telephone Communications
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	57,508	61,210
Telephone Communications | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Telephone Communications | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	74,013	75,410
Miscellaneous Health & Allied Services, not elsewhere classified
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	50,327	78,908
Miscellaneous Health & Allied Services, not elsewhere classified | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Miscellaneous Health & Allied Services, not elsewhere classified | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	28,079	0
Miscellaneous Equipment Rental & Leasing
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	49,423	49,776
Miscellaneous Equipment Rental & Leasing | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Miscellaneous Equipment Rental & Leasing | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	14,528	14,755
Electric Work
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	44,442	43,175
Electric Work | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Electric Work | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	288,586	339,179
Medical & Dental Laboratories
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	35,465	41,344
Medical & Dental Laboratories | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Medical & Dental Laboratories | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	35,465	41,344
Medical & Dental Laboratories
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	31,903	30,191
Medical & Dental Laboratories | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Medical & Dental Laboratories | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	108,266	118,456
Nonferrous Foundries (Castings)
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	29,796	45,610
Nonferrous Foundries (Castings) | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Nonferrous Foundries (Castings) | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	122,275	164,033
Coating, Engraving and Allied Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	29,323	47,249
Coating, Engraving and Allied Services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Coating, Engraving and Allied Services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	49,423	49,776
Home Health Care Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	28,537	29,361
Home Health Care Services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Home Health Care Services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	50,327	78,908
Motor Vehicles and Motor Vehicle Parts & Supplies
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	28,464	28,815
Motor Vehicles and Motor Vehicle Parts & Supplies | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Motor Vehicles and Motor Vehicle Parts & Supplies | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	9,750	10,000
Legal Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	28,079	0
Legal Services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Legal Services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	28,464	28,815
Petroleum and Petroleum Products
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	24,834	24,923
Petroleum and Petroleum Products | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Petroleum and Petroleum Products | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	31,903	30,191
Electronic Components & Accessories
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	23,266	24,000
Electronic Components & Accessories | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Electronic Components & Accessories | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	104,919	106,993
Grocery Stores
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	22,987	23,248
Grocery Stores | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Grocery Stores | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	10,110	10,098
Schools & Educational Services, not elsewhere classified
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	19,376	19,586
Schools & Educational Services, not elsewhere classified | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Schools & Educational Services, not elsewhere classified | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	24,834	24,923
Chemicals & Allied Products
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	15,881	15,923
Chemicals & Allied Products | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Chemicals & Allied Products | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	119,577	107,029
Chemicals & Allied Products
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	14,868	15,002
Chemicals & Allied Products | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Chemicals & Allied Products | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	29,796	45,610
Mailing, Reproduction, Commercial Art and Photography, and Stenographic
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	14,528	14,755
Mailing, Reproduction, Commercial Art and Photography, and Stenographic | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Mailing, Reproduction, Commercial Art and Photography, and Stenographic | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	19,376	19,586
Transportation, Equipment & Supplies (Except Motor Vehicles)
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	12,468	0
Transportation, Equipment & Supplies (Except Motor Vehicles) | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Transportation, Equipment & Supplies (Except Motor Vehicles) | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	100,791	102,182
Offices and Clinics of Other Health Practitioners
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	10,110	10,098
Offices and Clinics of Other Health Practitioners | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Offices and Clinics of Other Health Practitioners | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	12,468	0
Miscellaneous Plastic Products
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	9,750	10,000
Miscellaneous Plastic Products | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Miscellaneous Plastic Products | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	$ 57,508	$ 61,210