Statements Of Comprehensive Operations (USD $) In Thousands, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Net income	$ 4,615	$ 7,634	$ 85,564	$ 95,136
Unrecognized pension and postretirement benefit costs:
Net gain (loss) arising during period	19,700	0	102,664	(2,109)
Prior service benefit	0	0	97	0
Reclassification adjustments included in net income for amortization of:
Prior service benefit	(1,459)	(1,400)	(5,619)	(5,719)
Net loss	1,123	2,675	8,920	11,521
Net unrealized gains/losses on marketable securities:
Net holding gains arising during period	998	6,793	11,904	8,562
Reclassification adjustments for net (gains) losses included in net income	(2,865)	158	(3,576)	1,413
Net losses on cash flow hedges:
Reclassification adjustment for interest expense included in net income	107	101	417	392
Total other comprehensive income before income taxes	17,604	8,327	114,807	14,060
Income tax benefit (expense) related to items of other comprehensive income (loss):
Unrecognized pension and postretirement benefit costs	(7,422)	(570)	(40,418)	(1,479)
Net unrealized losses (gains) on marketable securities	357	(1,287)	(1,456)	(2,166)
Losses on cash flow hedges	(92)	(52)	(208)	(138)
Total income tax expense	(7,157)	(1,909)	(42,082)	(3,783)
Other comprehensive income, net of tax	10,447	6,418	72,725	10,277
Comprehensive income	$ 15,062	$ 14,052	$ 158,289	$ 105,413