STOCKHOLDERS' EQUITY (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Accumulated other comprehensive loss, pre-tax amounts:
Unrecognized net periodic benefit costs	$ (83,873)	$ (86,737)
Foreign currency translation	(692)	(662)
Total pre-tax amount	(84,565)	(87,399)
Accumulated other comprehensive loss, after-tax amounts:
Unrecognized net periodic benefit costs	(55,218)	(56,968)
Foreign currency translation	(423)	(404)
Total after-tax amount	$ (55,641)	$ (57,372)