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DERIVATIVE FINANCIAL INSTRUMENTS - Asset and Liability Managemen Add Info (Details Add Info)

v3.8.0.1
DERIVATIVE FINANCIAL INSTRUMENTS - Asset and Liability Managemen Add Info (Details Add Info) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Mar. 31, 2018
Dec. 31, 2017
Derivative [Line Items]    
Derivative, Notional Amount $ 7,852,000 $ 8,375,000
Additional information about the interest rate swaps used in companies Asset and Liability Management    
Notional Value $ 7,852,000 8,375,000
Average Maturity (years) 2 years 5 months 1 day  
Fair Value $ (176,000) $ (99,000)
Weighted-Average Rate Receive  
Weighted-Average Rate Pay  
Asset conversion swaps - Receive Fixed - Generic    
Additional information about the interest rate swaps used in companies Asset and Liability Management    
Notional Value $ 12,000  
Average Maturity (years) 1 year 11 months 15 days 0 years
Fair Value $ (32)  
Weighted-Average Rate Receive 2.20%  
Weighted-Average Rate Pay 1.78%  
Liability conversion swaps - Receive Fixed - Generic    
Additional information about the interest rate swaps used in companies Asset and Liability Management    
Notional Value $ 7,840,000 $ 8,375,000
Average Maturity (years)   2 years 6 months
Fair Value $ (175,630) $ (99,000)
Weighted-Average Rate Receive 1.57% 1.56%
Weighted-Average Rate Pay 1.88% 1.44%