Statements Of Consolidated Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Statement of Income and Comprehensive Income [Abstract]
Net Income	$ 25,304	$ 29,128	$ 92,750	$ 65,472
Other Comprehensive Income (Loss):
Foreign currency translation adjustment	674	(1,226)	(52)	477
Unrealized gain on available-for-sale security, net of deferred tax of $182, $7, $145 and $21, respectively	283	12	226	33
Employee benefit plans
Amortization of actuarial loss included in expense, net of deferred tax of $1,872, $976, $5,633 and $2,928, respectively	2,928	1,527	8,810	4,581
Other Comprehensive Income	3,885	313	8,984	5,091
Comprehensive Income	$ 29,189	$ 29,441	$ 101,734	$ 70,563