Consolidated Statements Of Comprehensive Operations (USD $) In Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Consolidated Statements Of Comprehensive Operations
Net income	$ 58,321	$ 60,182	$ 98,086	$ 93,138	$ 105,551	$ 101,099
Unrecognized pension and postretirement benefit costs:
Net loss arising during period	0	0	0	0	(9,874)	(48,580)
Prior service benefit	0	0	0	0	26,605	0
Reclassification adjustments included in net income for amortization of:
Prior service benefit	(1,453)	(688)	(4,358)	(2,065)	(5,047)	(2,754)
Net loss	1,625	843	4,878	2,530	5,722	2,936
Net unrealized gains (losses) on marketable securities:
Net holding gains (losses) arising during period	(7,503)	7,019	(4,914)	3,041	(1,290)	4,619
Reclassification adjustments for net (gains) losses included in net income	1,284	193	1,081	602	601	(2,246)
Net losses on cash flow hedges:
Reclassification adjustment for interest expense included in net income	93	86	269	252	355	333
Total other comprehensive income (loss) before income taxes	(5,954)	7,453	(3,044)	4,360	17,072	(45,692)
Income tax benefit (expense) related to items of other comprehensive income (loss):
Unrecognized pension and postretirement benefit costs	(65)	(57)	(196)	(169)	(6,314)	16,481
Net unrealized gains (losses) on marketable securities	1,171	(1,443)	654	(729)	26	(475)
Losses on cash flow hedges	(35)	(31)	(101)	(91)	(132)	(121)
Total income tax benefit (expense)	1,071	(1,531)	357	(989)	(6,420)	15,885
Other comprehensive income (loss), net of tax	(4,883)	5,922	(2,687)	3,371	10,652	(29,807)
Comprehensive income	$ 53,438	$ 66,104	$ 95,399	$ 96,509	$ 116,203	$ 71,292