LOANS - Schedule of Industry and Rate Sensitivity (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	$ 2,115,783	$ 1,887,182
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	2,115,783	1,887,182
Aircraft and Parts
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	41,064	41,342
Aircraft and Parts | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Aircraft and Parts | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	41,064	41,342
Arrangement of Transportation of Freight & Cargo
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	21,632
Arrangement of Transportation of Freight & Cargo | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Arrangement of Transportation of Freight & Cargo | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	21,632
Coating, Engraving & Allied Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	49,767	57,223
Coating, Engraving & Allied Services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Coating, Engraving & Allied Services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	49,767	57,223
Commercial Fishing
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	242,185
Commercial Fishing | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Commercial Fishing | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	242,185
Computer Programming, Data Processing & Other Computer Related Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	347,287	0
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	347,287	0
Drugs
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	35,918	35,882
Drugs | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Drugs | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	35,918	35,882
Electrical Work
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	42,372	41,760
Electrical Work | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Electrical Work | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	42,372	41,760
Electronic Components & Accessories
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	24,000	24,059
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	24,000	24,059
Engineering, Architectural, and Surveying
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	77,284	80,748
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	77,284	80,748
Grocery Stores
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	23,292	23,431
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	23,292	23,431
Home Health Care Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	29,391	0
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	29,391	0
Insurance Agents, Brokers and Service
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	76,444	48,942
Insurance Agents, Brokers and Service | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Insurance Agents, Brokers and Service | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	76,444	48,942
Mailing, Reproduction, Commercial Art and Photography, and Stenographic
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	14,770	14,843
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	14,770	14,843
Management & Public Relations Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	339,319	487,046
Management & Public Relations Services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Management & Public Relations Services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	339,319	487,046
Medical & Dental Laboratories
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	41,467	26,858
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	41,467	26,858
Medical & Dental Laboratories
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	118,420	118,248
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	118,420	118,248
Metal Cans & Shipping Containers
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	215,709	19,622
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	215,709	19,622
Miscellaneous Equipment Rental & Leasing
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	49,732	49,552
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	49,732	49,552
Miscellaneous Health & Allied Services, not elsewhere classified
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	77,551	56,003
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	77,551	56,003
Miscellaneous Plastic Products
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	10,000	9,953
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	10,000	9,953
Motor Vehicles and Motor Vehicle Equipment
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	16,563
Motor Vehicles and Motor Vehicle Equipment | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Motor Vehicles and Motor Vehicle Equipment | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	16,563
Motor Vehicles and Motor Vehicle Parts & Supplies
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	28,877	29,046
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	28,877	29,046
Nonferrous Foundries (Castings)
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	12,918	12,948
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	12,918	12,948
Offices & Clinics of Doctors of Medicine
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	107,066	97,877
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	107,066	97,877
Offices & Clinics of other Health Practitioners
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	10,123	21,100
Offices & Clinics of other Health Practitioners | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Offices & Clinics of other Health Practitioners | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	10,123	21,100
Petroleum and Petroleum Products
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	24,957	0
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	24,957	0
Research, Development & Testing Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	94,877	84,278
Research, Development & Testing Services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Research, Development & Testing Services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	94,877	84,278
Research, Development & Testing Services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	45,610	33,381
Research, Development & Testing Services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Research, Development & Testing Services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	45,610	33,381
Schools & Educational Services, not elsewhere classified
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	19,635	19,805
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	19,635	19,805
Services Allied with the Exchange of Securities
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	14,877
Services Allied with the Exchange of Securities | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Services Allied with the Exchange of Securities | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	14,877
Surgical, Medical & Dental Instruments & Supplies
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	96,702	96,607
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	96,702	96,607
Telephone Communications
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	61,231	61,371
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	$ 61,231	$ 61,371