CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement Of Other Comprehensive Income [Abstract]
NET INCOME	$ 166,895	$ 274,436	$ 296,381
OTHER COMPREHENSIVE INCOME, NET OF TAXES:
Pension adjustment	4,928	(1,707)	(3,048)
Cash flow hedge			387
Foreign currency translation	(778)	265	(138)
Unrealized loss on securities and reclassification adjustments	(19)	(158)	(314)
COMPREHENSIVE INCOME	$ 171,026	$ 272,836	$ 293,268