ASSETS HELD FOR SALE (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Dec. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	$ 94,684	$ 90,505	$ 103,522	$ 204,354
Accounts receivable	66,153	71,327
Inventories	19,827	22,269
Other current assets	21,119	25,762
Total current assets	210,483	234,570
Property and equipment, net	361,843	405,151
Total assets	588,353	657,981	$ 1,129,777
Accounts payable	10,058	10,357
Total current liabilities	98,608	$ 116,795
Russian Business Unit [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	616
Accounts receivable	1,401
Inventories	113
Other current assets	35
Total current assets	2,165
Property and equipment, net	535
Total assets	2,700
Accounts payable	322
Total current liabilities	322
Net Assets	$ 2,378