Statements Of Consolidated Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement of Comprehensive Income [Abstract]
Net Income	$ 30,557	$ 25,304	$ 87,459	$ 92,750
Other Comprehensive Income (Loss):
Foreign currency translation adjustment	305	674	563	(52)
Unrealized gain on available-for-sale security, net of deferred tax of $0, $182, $0 and $145, respectively	0	283	0	226
Employee benefit plans
Net actuarial loss included in net periodic benefit expense or income, net of deferred tax of $1,892, $1,988, $5,672 and $5,982, respectively	2,956	3,110	8,871	9,355
Amortization of prior service cost or credit included in net periodic benefit expense or income, net of deferred tax of $61, $116, $184 and $349, respectively	95	(182)	284	(545)
Employee benefit plans	3,051	2,928	9,155	8,810
Total Other Comprehensive Income	3,356	3,885	9,718	8,984
Comprehensive Income	$ 33,913	$ 29,189	$ 97,177	$ 101,734