Accumulated Other Comprehensive Income (Loss) (Reclassification) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net		$ (756)	$ (107)	$ (1,404)	$ (1,374)
Tax benefit (expense)		(9,595)	(8,149)	(21,392)	(19,647)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized gain (loss) on derivative instruments [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net		(1)		143
Tax benefit (expense)		0		(50)
Net of tax		(1)		93
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized gains and losses on marketable securities [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Other income (expense), net			1		323
Tax benefit (expense)			0		(113)
Net of tax			1		210
Reclassification out of Accumulated Other Comprehensive Income [Member] | Amortization of defined benefit pension and other post-retirement benefit items [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Actuarial losses	[1]	428	203	1,243	607
Tax benefit (expense)		(151)	(71)	(435)	(212)
Net of tax		$ 277	$ 132	$ 808	$ 395

[1] These accumulated other comprehensive income (loss) components are included in the computation of net periodic pension cost. See Note 9 - "Pension Benefits and Other Postretirement Benefit Plans" for additional details.