Segments and Geographic Information (Reconciliation of Segment EBIT to Net Income) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014 segment		Dec. 31, 2013		Dec. 31, 2012
Segment Reporting Information [Line Items]
Number of reportable segments	3
Net Sales:
Net sales	$ 852,492		$ 818,811		$ 825,287
Segment EBIT:
Segment EBIT	113,559		114,534		115,346
Reconciliation of Segment EBIT to Net Income:
Retained corporate costs	(30,558)		(21,653)		(24,678)
Loss on redemption of debt (note 6)	(47,191)		(2,518)		(31,075)
Severance	0		0		(5,150)
Pension curtailment and settlement charge	(774)		(2,252)		(4,306)
Furnace malfunction (note 18)	4,782		(4,428)		0
Environmental obligation (note 18)	(315)		0		0
Restructuring charges (note 7)	(985)		(6,544)		0
Derivatives (1)	(1,247)	[1]	(916)	[1]	265	[1]
Abandoned property (note 18)	0		(1,781)		0
Executive retirement	(875)		(736)		0
Interest expense	(22,866)		(32,006)		(37,727)
Income taxes	(8,567)		(13,241)		(5,709)
Net income	4,963		28,459		6,966
Depreciation & Amortization:
Depreciation and amortization	40,388		43,969		41,471
Capital Expenditures:
Capital Expenditures	54,393		49,407		32,720
Segment Assets:
Accounts Receivable, Net and Inventory, Net	260,934		252,670
Americas
Net Sales:
Net sales	591,391		560,840		580,734
Segment EBIT:
Segment EBIT	98,460		100,534		95,833
Depreciation & Amortization:
Depreciation and amortization	22,856		24,953		24,661
Capital Expenditures:
Capital Expenditures	44,444		31,404		24,021
Segment Assets:
Accounts Receivable, Net and Inventory, Net	163,074		158,131
EMEA
Net Sales:
Net sales	147,587		146,455		134,778
Segment EBIT:
Segment EBIT	5,726		874		(714)
Depreciation & Amortization:
Depreciation and amortization	10,061		10,449		9,746
Capital Expenditures:
Capital Expenditures	6,471		7,787		5,459
Segment Assets:
Accounts Receivable, Net and Inventory, Net	48,557		50,115
U.S. Sourcing
Net Sales:
Net sales	80,782		78,302		72,234
Segment EBIT:
Segment EBIT	6,995		9,752		11,381
Depreciation & Amortization:
Depreciation and amortization	25		33		40
Capital Expenditures:
Capital Expenditures	0		30		0
Segment Assets:
Accounts Receivable, Net and Inventory, Net	33,328		27,202
Other Segments
Net Sales:
Net sales	32,732		33,214		37,541
Segment EBIT:
Segment EBIT	2,378		3,374		8,846
Depreciation & Amortization:
Depreciation and amortization	6,179		7,275		5,777
Capital Expenditures:
Capital Expenditures	1,983		7,437		2,196
Segment Assets:
Accounts Receivable, Net and Inventory, Net	15,975		17,222
Corporate
Depreciation & Amortization:
Depreciation and amortization	1,267		1,259		1,247
Capital Expenditures:
Capital Expenditures	$ 1,495		$ 2,749		$ 1,044

[1] Derivatives relate to hedge ineffectiveness and mark-to-market adjustments on our natural gas contracts that have been de-designated and those for which we did not elect hedge accounting. 2013 and 2012 also include hedge ineffectiveness on our interest rate swap.