Quarterly report pursuant to Section 13 or 15(d)

SECURITIES (Narrative) (Details)

v3.19.3
SECURITIES (Narrative) (Details)
 3 Months Ended 9 Months Ended 12 Months Ended
Sep. 30, 2019
USD ($)
security
Sep. 30, 2019
USD ($)
security
Dec. 31, 2018
USD ($)
security
Schedule of Investments [Line Items]      
Available-for-sale securities that had been in a continuous loss position for more than 12 months, fair value $ 99,846,000 $ 99,846,000 $ 385,433,000
Available-for-sale securities that had been in a continuous loss position for more than 12 months, unrealized loss 805,000 805,000 $ 10,184,000
Individual held-to-maturity securities in continuous loss position for more than 12 months 0 $ 0  
Federal Home Loan Bank requires Bank to maintain percentage of stock equal to outstanding borrowings   4.25% 4.25%
Held-to-maturity, securities in unrealized loss positions, qualitative disclosure, number of positions (security) | security     0
Percentage of Federal Reserve Bank of Richmond reserve   6.00% 6.00%
Restricted equity securities consist of Federal Reserve Bank stock 67,000,000.0 $ 67,000,000.0 $ 52,600,000
Federal Home Loan Bank stock 65,400,000 65,400,000 $ 72,000,000.0
Credit-related OTTI 0    
Available-for-sale Securities      
Schedule of Investments [Line Items]      
Available-for-sale securities that had been in a continuous loss position for more than 12 months, fair value $ 99,900,000 $ 99,900,000  
Number of available-for-sale securities that had been in a continuous loss position | security 56 56 138