Accumulated Other Comprehensive Income (Loss) - Changes in Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	$ (134,648)	$ (162,478)	$ (140,363)	$ (166,814)
Other comprehensive (loss) income before reclassifications	(3,529)	1,519	(3,214)	(2,503)
Amounts reclassified from accumulated other comprehensive income (net of tax $(5,158) and $(7,983)	2,701	4,179	8,101	12,537
Net current-period other comprehensive (loss) income	(828)	5,698	4,887	10,034
Ending balance	(135,476)	(156,780)	(135,476)	(156,780)
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Tax	1,719	2,661	5,158	7,983
Foreign Currency
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	6,968	8,018	6,653	12,040
Other comprehensive (loss) income before reclassifications	(3,529)	1,519	(3,214)	(2,503)
Amounts reclassified from accumulated other comprehensive income (net of tax $(5,158) and $(7,983)	0	0	0	0
Net current-period other comprehensive (loss) income	(3,529)	1,519	(3,214)	(2,503)
Ending balance	3,439	9,537	3,439	9,537
Pension and Other Postretirement Benefits
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning balance	(141,616)	(170,496)	(147,016)	(178,854)
Other comprehensive (loss) income before reclassifications	0	0	0	0
Amounts reclassified from accumulated other comprehensive income (net of tax $(5,158) and $(7,983)	2,701	4,179	8,101	12,537
Net current-period other comprehensive (loss) income	2,701	4,179	8,101	12,537
Ending balance	$ (138,915)	$ (166,317)	$ (138,915)	$ (166,317)