INVESTMENTS INVESTMENTS - Additional Information (Details) - USD ($) $ in Thousands |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2016 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
|
| Gain (Loss) on Investments [Line Items] | ||||
| Available-for-sale Securities, Gross Realized Gains (Losses), Sale Proceeds | $ 99,400 | $ 14,700 | $ 206,900 | $ 68,600 |
| Available-for-sale Securities, Gross Realized Gains | 800 | 400 | 1,200 | 1,500 |
| Available-for-sale Securities, Gross Realized Losses | 500 | 0 | 1,000 | 0 |
| Proceeds from Sale of Held-to-maturity Securities | $ 4,862 | $ 0 | 4,862 | $ 0 |
| Held-to-maturity Securities, Sold Security, Realized Gain (Loss) | $ 44 | |||