LOANS - Schedule of Industry and Rate Sensitivity (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	$ 1,802,607	$ 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	1,802,607	1,887,182
Aircraft and parts
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	41,394	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	41,394	41,342
Arrangement of transportation of freight & cargo
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	21,715	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	21,715	21,632
Coating, engraving and allied services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	54,532	57,223
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	54,532	57,223
Computer programming, data processing & other computer related services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	282,060	242,185
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	282,060	242,185
Drugs
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	35,926	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	35,926	35,882
Electrical work
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	41,598	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	41,598	41,760
Electronic components & accessories
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	24,083	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	24,083	24,059
Engineering, architectural & surveying
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	109,823	80,748
Engineering, architectural & surveying | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Engineering, architectural & surveying | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	109,823	80,748
Grocery stores
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	23,394	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	23,394	23,431
Insurance agents, brokers and services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	48,661	48,942
Insurance agents, brokers and services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Insurance agents, brokers and services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	48,661	48,942
Mailing, reproduction, commercial art and photography, and stenographic
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	14,819	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	14,819	14,843
Management and public relations services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	312,807	487,046
Management and public relations services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Management and public relations services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	312,807	487,046
Medical and dental laboratories
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	26,811	26,858
Medical and dental laboratories | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Medical and dental laboratories | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	26,811	26,858
Metal cans & shipping containers
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	118,385	118,248
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	118,385	118,248
Miscellaneous business services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	19,581	19,622
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	19,581	19,622
Miscellaneous equipment rental and leasing
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	49,674	49,552
Miscellaneous equipment rental and leasing | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Miscellaneous equipment rental and leasing | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	49,674	49,552
Miscellaneous health and allied services, not elsewhere classified
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	69,217	56,003
Miscellaneous health and allied services, not elsewhere classified | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Miscellaneous health and allied services, not elsewhere classified | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	69,217	56,003
Miscellaneous plastic products
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	10,037	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	10,037	9,953
Motor vehicles and motor vehicle equipment
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	16,417	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	16,417	16,563
Motor vehicles and motor vehicle parts and supplies
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	28,984	29,046
Motor vehicles and motor vehicle parts and supplies | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Motor vehicles and motor vehicle parts and supplies | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	28,984	29,046
Nonferrous foundries (castings)
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	12,933	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	12,933	12,948
Offices and clinics of doctors of medicine
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	97,841	97,877
Offices and clinics of doctors of medicine | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Offices and clinics of doctors of medicine | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	97,841	97,877
Offices of clinics and other health practitioners
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	21,051	21,100
Offices of clinics and other health practitioners | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Offices of clinics and other health practitioners | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	21,051	21,100
Public warehousing and storage
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	97,245	84,278
Public warehousing and storage | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Public warehousing and storage | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	97,245	84,278
Research, development and testing services
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	45,676	33,381
Research, development and testing services | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Research, development and testing services | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	45,676	33,381
Schools and educational services, not elsewhere classified
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	19,809	19,805
Schools and educational services, not elsewhere classified | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Schools and educational services, not elsewhere classified | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	19,809	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, and dental instruments and supplies
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	96,768	96,607
Surgical, medical, and dental instruments and supplies | Fixed Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	0	0
Surgical, medical, and dental instruments and supplies | Floating Rate
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	96,768	96,607
Telephone communications
Schedule of Held-to-maturity Securities [Line Items]
Corporate debt	61,366	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	$ 61,366	$ 61,371