Comprehensive Income (Components Of Comprehensive Income) (Details) (USD $) In Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Net earnings	$ 8,449	$ 11,743	$ 16,145	$ 12,938
Amortization of prior service credit included in net periodic cost, net of tax	(1,197)	(1,180)	(2,395)	(2,367)
Amortization of actuarial loss included in net periodic cost, net of tax	2,040	1,743	4,235	3,905
Curtailment gain, net of tax				(156)
Recognition of deferred taxes related to actuarial gain on OPEB obligations		(113)		5,693
Other comprehensive income, net of tax	843	450	1,840	7,075
Comprehensive income	9,292	12,193	17,985	20,013
Amortization of prior service credit included in net periodic cost, tax effect	(766)	(755)	(1,531)	(1,513)
Amortization of actuarial loss included in net periodic cost, net of tax, tax effect	1,303	1,115	2,706	2,498
Curtailment gain, tax effect	0	0	0	(100)
Pension Plans [Member]
Other comprehensive income, net of tax	1,596	1,360	3,233	2,779
Other Postretirement Employee Benefits [Member]
Other comprehensive income, net of tax	$ (753)	$ (910)	$ (1,393)	$ 4,296