OTHER LONG-TERM LIABILITIES (Tables)

12 Months Ended

Dec. 31, 2017

Other Liabilities Disclosure [Abstract]

Schedule of other long-term liabilities

Other long-term liabilities consisted of the following:

	December 31, 2017		December 31, 2016
Defined benefit pension plan liabilities	$	63,579	$	60,007
Post-retirement medical plan liabilities	21,527		22,740
Environmental liabilities	138,545		142,935
Other	310		429
Total other long-term liabilities	$	223,961	$	226,111