Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Other Comprehensive Income (Loss), Net of Tax	$ 45,140		$ (40,469)		$ 3,644
Accumulated other comprehensive income (loss)	(126,261)		(81,121)
Tax effect, amortization of prior service cost, pension and other post-retirement benefits	(37)		(38)
Tax effect of amortization of net gain/loss, pension and other post-retirement benefits	(1,583)		(3,677)
Change in net gain, pension and other post-retirement benefits, Tax	25,203		(20,218)
Tax effect on gain/loss derivative instruments in OCI before reclassified to net income	162		104
Tax effect on gain/loss on derivative instruments reclassified to net income	(323)		(66)
Accumulated Translation Adjustment [Member]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(3,833)		2,296
Reclassification to net income, foreign currency translation, net of tax	(2,624)		0
Other Comprehensive Income (Loss), Net of Tax	(6,457)		2,296
Accumulated other comprehensive income (loss)	(20,676)		(14,219)		(16,515)
Accumulated Defined Benefit Plans Adjustment [Member]
Other Comprehensive Income (Loss), Net of Tax	(38,947)	[1]	38,234	[1]
Accumulated other comprehensive income (loss)	(105,264)	[1]	(66,317)	[1]	(104,551)	[1]
Accumulated Defined Benefit Plan & SERP, Net Prior Service Cost [Member]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	61	[1]	60	[1]
Accumulated Defined Benefit Plan & SERP, Amortization of Net Loss [Member]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	2,614	[1]	5,875	[1]
Accumulated Defined Benefit Plan & SERP, Change in net gain [Member]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(41,622)	[1]	32,299	[1]
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax	(268)	[2]	(172)	[2]
Reclassification to net income, foreign currency translation, net of tax	532	[2]	111	[2]
Other Comprehensive Income (Loss), Net of Tax	264	[2]	(61)	[2]
Accumulated other comprehensive income (loss)	$ (321)	[2]	$ (585)	[2]	$ (524)	[2]

[1] (a) These accumulated other comprehensive income components are included in the computation of net periodic pension cost (see Note 14, Pension Plans for additional information)

[2] (b) See Note 6, Derivative Financial Instruments, for additional information regarding our derivative instruments.