Shareholders' Equity (Schedule Of Changes In Equity) (Details) (USD $) In Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Shareholders' Equity [Abstract]
Net income (loss)	$ 29,128	$ (8,228)	$ 65,472	$ 1,598
Foreign currency translation adjustment	(1,226)	799	477	(1,639)
Unrealized gain (loss) on available-for-sale security, net of deferred tax of $7, $5, $21, and $17, respectively	12	(8)	33	26
Employee benefit plans, net of deferred tax of $976, $812, $2,928, and $4,699 respectively	1,527	1,268	4,581	6,058
Comprehensive income (loss)	29,441	(6,169)	70,563	6,043
Unrealized gain (loss) on available-for-sale security, deferred tax	7	5	21	17
Employee benefit plans, deferred tax	$ 976	$ 812	$ 2,928	$ 4,699