ACCRUED LIABILITIES (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
ACCRUED LIABILITIES [Abstract]
Pension and other postretirement benefits	$ 23,392	$ 55,244
Compensation and related employee costs	43,732	31,205
Interest	27,711	25,477
Income taxes	26,088	9,878
Taxes and other	16,572	9,237
Total accrued liabilities	$ 137,495	$ 131,041