STATEMENTS OF COMPREHENSIVE OPERATIONS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net income	$ 88,583	$ 90,846	$ 103,539
Unrecognized pension and postretirement benefit costs:
Net gain (loss) arising during period	82,964	(2,109)	(77,678)
Prior service benefit	97	0	0
Reclassification adjustments included in net income for amortization of:
Prior service benefit	(5,560)	(5,762)	(5,812)
Net loss	10,472	11,971	6,505
Net unrealized gains/losses on marketable securities:
Net holding gains arising during period	17,699	9,927	1,570
Reclassification adjustments for net (gains) losses included in net income	(553)	1,042	1,358
Net losses on cash flow hedges:
Reclassification adjustment for interest expense included in net income	411	385	361
Total other comprehensive income (loss) before income taxes	105,530	15,454	(73,696)
Income tax benefit (expense) related to items of other comprehensive income (loss):
Unrecognized pension and postretirement benefit costs	(33,566)	(1,464)	30,134
Net unrealized gains on marketable securities	(3,100)	(2,438)	(563)
Losses on cash flow hedges	(168)	(131)	(203)
Total income tax benefit (expense)	(36,834)	(4,033)	29,368
Other comprehensive income (loss), net of tax	68,696	11,421	(44,328)
Comprehensive income	$ 157,279	$ 102,267	$ 59,211