INVESTMENTS (Details 3) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Available-for-sale, Amortized Cost  
Within 1 year $ 334,207
After 1 year through 5 years 260,157
Total 594,364
Available-for-sale, Estimated Fair Value  
Within 1 year 334,234
After 1 year through 5 years 260,547
Total 594,781
Held-to-maturity, Amortized Cost  
Within 1 year 1,619
Total 1,619
Held-to-maturity, Estimated Fair Value  
Within 1 year 1,619
Total $ 1,619