Statements Of Consolidated Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement of Other Comprehensive Income [Abstract]
Net Income	$ 42,897	$ 41,800	$ 56,902	$ 67,446
Other Comprehensive Income (Loss):
Foreign currency translation adjustment	(182)	(1,456)	258	(726)
Unrealized loss on available-for-sale security, net of deferred tax of $0, $82, $0 and $37, respectively	0	(127)	0	(57)
Employee benefit plans
Net loss included in net periodic benefit expense or income, net of deferred tax of $1,859, $2,019, $3,781 and $3,993, respectively	2,907	3,112	5,914	6,246
Amortization of prior service cost or credit included in net periodic benefit expense or income, net of deferred tax of $61, $116, $122 and $232, respectively	95	(181)	190	(364)
Employee benefit plans	3,002	2,931	6,104	5,882
Total Other Comprehensive Income	2,820	1,348	6,362	5,099
Comprehensive Income	$ 45,717	$ 43,148	$ 63,264	$ 72,545