Segments and Geographic Information (Reconciliation of Segment EBIT to Net Income) (Details) $ in Thousands		3 Months Ended				12 Months Ended
		Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($) segment	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | segment						3
Net Sales:
Net sales		$ 219,145	$ 201,784	$ 214,051	$ 187,365	$ 822,345	$ 852,492	$ 818,811
Segment EBIT:
Segment EBIT		27,551	28,281	33,180	19,052	108,064	113,559	114,534
Reconciliation of Segment EBIT to Net Income:
Retained corporate costs						(34,645)	(30,558)	(21,653)
Loss on redemption of debt (note 6)						0	(47,191)	(2,518)
Pension settlement charges (note 9)						(21,693)	(774)	(2,252)
Furnace malfunction (note 18)						0	4,782	(4,428)
Environmental obligation (note 18)						(157)	(315)	0
Restructuring charges (note 7)						0	(985)	(6,544)
Reorganization charges (1)	[1]					(4,316)	0	0
Derivatives (2)	[2]					218	(1,247)	(916)
Abandoned property (note 18)						0	0	(1,781)
Executive termination						(870)	(875)	(736)
Interest expense						(18,484)	(22,866)	(32,006)
(Provision) benefit for income taxes						38,216	(8,567)	(13,241)
Net income						66,333	4,963	28,459
Depreciation & Amortization:
Depreciation and amortization		11,426	10,633	10,469	10,184	42,712	40,388	43,969
Capital Expenditures:
Capital Expenditures		6,656	8,244	16,577	16,659	48,136	54,393	49,407
Segment Assets:
Accounts Receivable, Net and Inventory, Net		272,406				272,406	260,934	252,670
U.S. & Canada
Net Sales:
Net sales		139,774	120,600	127,435	109,919	497,728	482,094	459,575
Segment EBIT:
Segment EBIT		23,389	20,842	25,315	10,860	80,406	72,546	76,445
Depreciation & Amortization:
Depreciation and amortization		3,425	3,010	2,987	2,792	12,214	10,319	12,685
Capital Expenditures:
Capital Expenditures		1,672	2,666	9,931	10,837	25,106	21,927	9,022
Segment Assets:
Accounts Receivable, Net and Inventory, Net		140,840				140,840	129,676	115,184
Latin America
Net Sales:
Net sales		40,231	42,372	44,614	39,852	167,069	190,079	179,567
Segment EBIT:
Segment EBIT		3,646	6,280	5,003	7,088	22,017	32,909	33,841
Depreciation & Amortization:
Depreciation and amortization		4,361	3,662	3,430	3,285	14,738	12,562	12,301
Capital Expenditures:
Capital Expenditures		774	3,160	4,329	3,681	11,944	22,517	22,412
Segment Assets:
Accounts Receivable, Net and Inventory, Net		68,599				68,599	66,726	70,149
EMEA
Net Sales:
Net sales		31,457	30,572	32,126	28,509	122,664	147,587	146,455
Segment EBIT:
Segment EBIT		(23)	254	1,786	(766)	1,251	5,726	874
Depreciation & Amortization:
Depreciation and amortization		2,065	2,131	2,137	2,177	8,510	10,061	10,449
Capital Expenditures:
Capital Expenditures		2,272	1,726	1,338	1,437	6,773	6,471	7,787
Segment Assets:
Accounts Receivable, Net and Inventory, Net		48,924				48,924	48,557	50,115
Other Segments
Net Sales:
Net sales		7,683	8,240	9,876	9,085	34,884	32,732	33,214
Segment EBIT:
Segment EBIT		539	905	1,076	1,870	4,390	2,378	3,374
Depreciation & Amortization:
Depreciation and amortization		1,421	1,462	1,481	1,491	5,855	6,179	7,275
Capital Expenditures:
Capital Expenditures		864	451	357	183	1,855	1,983	7,437
Segment Assets:
Accounts Receivable, Net and Inventory, Net		14,043				14,043	15,975	17,222
Corporate
Depreciation & Amortization:
Depreciation and amortization		154	368	434	439	1,395	1,267	1,259
Capital Expenditures:
Capital Expenditures		$ 1,074	$ 241	$ 622	$ 521	$ 2,458	$ 1,495	$ 2,749

[1] Management reorganization to support our growth strategy.

[2] Derivatives relate to hedge ineffectiveness on our natural gas contracts and interest rate swap, as well as, mark-to-market adjustments on our natural gas contracts that have been de-designated and those for which we did not elect hedge accounting.