Shareholders' Equity (Schedule Of Change In Equity) (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Shareholders' Equity
Net income	$ 29,422	$ 13,863	$ 36,344	$ 9,826
Foreign currency translation adjustment	709	(1,392)	1,703	(2,438)
Unrealized gain (loss) on available-for-sale security, net of deferred tax of $10, $16, $14, and $22, respectively	(16)	(24)	21	34
Employee benefit plans, net of deferred tax of $941, $827, $1,952, and $3,887, respectively	1,472	1,294	3,054	4,790
Comprehensive income	31,587	13,741	41,122	12,212
Unrealized gain (loss) on available-for-sale security, deferred tax	10	16	14	22
Employee benefit plans, deferred tax	$ 941	$ 828	$ 1,952	$ 3,887