v3.10.0.1
FAIR VALUE MEASUREMENTS Table 2 - Estimated Fair Values and Carrying Amounts of Long-Term Debt (Details) - USD ($)
$ in Thousands
Sep. 30, 2018
Dec. 31, 2017
Fair Value Disclosures [Abstract]    
Fair value, long-term debt $ 3,409,199 $ 3,677,622
Carrying amount, long-term debt $ 3,376,852 $ 3,613,059