Segments (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015 segment		Mar. 31, 2014
Segment Reporting Information [Line Items]
Number of reportable segments	3
Net Sales:
Net sales	$ 187,365		$ 181,581
Segment EBIT:
Segment EBIT	19,052		16,555
Reconciliation of Segment EBIT to Net Income (Loss):
Retained corporate costs	(9,495)		(7,195)
Furnace malfunction (note 14)	0		(5,306)
Restructuring charges (note 5)	0		(985)
Derivatives (1)	(399)	[1]	70	[1]
Executive retirement	(235)		0
Interest expense	(4,523)		(7,701)
Income taxes	(1,288)		1,178
Net income (loss)	3,112		(3,384)
Depreciation & Amortization:
Depreciation and amortization	10,184		10,676
Capital Expenditures:
Capital Expenditures	16,659		9,901
Americas [Member]
Net Sales:
Net sales	128,372		121,925
Segment EBIT:
Segment EBIT	16,323		14,989
Depreciation & Amortization:
Depreciation and amortization	6,071		5,959
Capital Expenditures:
Capital Expenditures	14,518		7,132
EMEA [Member]
Net Sales:
Net sales	28,509		34,398
Segment EBIT:
Segment EBIT	(766)		253
Depreciation & Amortization:
Depreciation and amortization	2,177		2,626
Capital Expenditures:
Capital Expenditures	1,437		1,561
U.S. Sourcing [Member]
Net Sales:
Net sales	21,399		17,734
Segment EBIT:
Segment EBIT	1,625		868
Depreciation & Amortization:
Depreciation and amortization	6		7
Capital Expenditures:
Capital Expenditures	0		0
Other Segments [Member]
Net Sales:
Net sales	9,085		7,524
Segment EBIT:
Segment EBIT	1,870		445
Depreciation & Amortization:
Depreciation and amortization	1,491		1,644
Capital Expenditures:
Capital Expenditures	183		572
Corporate [Member]
Depreciation & Amortization:
Depreciation and amortization	439		440
Capital Expenditures:
Capital Expenditures	$ 521		$ 636

[1] 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.