FAIR VALUE MEASUREMENTS (Details) - Recurring basis $ in Thousands	Mar. 31, 2018 USD ($)
Carrying Amount
Assets:
Marketable equity securities	$ 3,274
Liabilities:
Debt	431,037
Amount of equity component of convertible notes	77,000
Fair Value
Assets:
Marketable equity securities	3,274
Total assets	3,274
Liabilities:
Debt	390,280
Total liabilities	390,280
Level 1
Assets:
Marketable equity securities	3,274
Total assets	3,274
Liabilities:
Debt	390,280
Total liabilities	$ 390,280