Accumulated Other Comprehensive Income (Loss) (Reclassification) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Realized gain (loss)									$ (1,240)		$ (208)		$ 1,942
Income tax expense (benefit)									11,226		(46,484)		11,518
Income (loss) from continuing operations	11,528	13,572	5,583	6,976	5,179	59,124	6,417	(1,586)	37,659		69,134		44,250
Income (loss) before income tax expense (benefit)									48,885		22,650		55,768
Amounts reclassified from accumulated other comprehensive income (loss) for the period ended December 31, 2013 [Member] | Unrealized gain (loss) on marketable securities [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)											(1,555)
Income (loss) from continuing operations											(1,168)
Realized gain (loss)											(2,723)
Amounts reclassified from accumulated other comprehensive income (loss) for the period ended December 31, 2013 [Member] | Unrealized gain (loss) on derivative instruments [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Realized gain (loss)								415	363
Income tax expense (benefit)								145	127
Income (loss) from continuing operations								270	236
Amounts reclassified from accumulated other comprehensive income (loss) for the period ended December 31, 2013 [Member] | Amortization of defined benefit pension and other post-retirement benefit items: [Member]
Reclassification out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense (benefit)									(1,838)		(2,028)
Income (loss) from continuing operations									(3,412)		(3,768)
Prior service costs									1,431	[1]	12	[1]
Actuarial losses									3,819	[1]	5,784	[1]
Income (loss) before income tax expense (benefit)									$ (5,250)		$ (5,796)

[1] These accumulated other comprehensive income components are included in the computation of net periodic pension cost. See Note 10 - "Pension Benefits and Retirement Health and Life Insurance Benefits" for additional details.