Accumulated Other Comprehensive Income (Loss) (Reclassification) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Realized gain (loss)	$ 0		$ 0	$ 0		$ (3,245)
Total before tax	(19,781)		(11,017)	(37,493)		(16,103)
Tax benefit (expense)	(6,209)		48,107	(11,361)		47,852
Net of tax	(13,572)		(59,124)	(26,132)		(63,955)
Unrealized gain (loss) on marketable securities [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Realized gain (loss)			0			(2,723)
Tax benefit (expense)			0			1,555
Net of tax			0			1,168
Amortization of defined benefit pension and other post-retirement benefit items [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Prior service costs	0	[1]	3	1,545	[1]	9
Actuarial losses	545	[1]	3,436	3,235	[1]	6,408
Total before tax	545		3,439	4,780		6,417
Tax benefit (expense)	191		1,204	1,673		2,246
Net of tax	$ 354		$ 2,235	$ 3,107		$ 4,171

[1] These accumulated other comprehensive income components are included in the computation of net periodic pension cost. See Note 8 - "Pension Benefits and Other Postretirement Benefit Plans" for additional details.