Segment Information (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011 segment	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Segment Information
Number of reportable segments									3
Segment Information
Net sales	$ 130,732,000	$ 162,366,000	$ 177,812,000	$ 132,536,000	$ 119,606,000	$ 146,447,000	$ 165,614,000	$ 123,820,000	$ 603,446,000	$ 555,487,000	$ 526,544,000
Sales to Other Segments									16,739,000	13,270,000	7,685,000
Income (Loss) from Operations	5,684,000	24,882,000	31,208,000	12,283,000	(1,858,000)	29,252,000	33,937,000	17,092,000	74,057,000	78,424,000	31,496,000
Depreciation and amortization									20,751,000	22,861,000	29,387,000
Impairment of Goodwill									1,282,000	10,727,000
Impairment of long-lived asset									1,094,000	419,000
Significant non-cash charges									6,837,000	3,689,000	2,152,000
Income tax expense (benefit)	818,000	10,052,000	11,754,000	5,263,000	2,535,000	10,801,000	12,773,000	7,130,000	27,886,000	33,239,000	17,356,000
Capital expenditures and acquisitions									77,916,000	33,555,000	39,487,000
Total Assets	836,087,000				874,709,000				836,087,000	874,709,000	843,805,000
Cash and short-term investments	213,817,000				335,049,000				213,817,000	335,049,000	250,381,000	170,750,000
Continuing Operations
Segment Information
Depreciation and amortization									20,751,000	21,151,000	25,364,000
North America
Segment Information
Net sales									474,722,000	444,622,000	427,428,000
Sales to Other Segments									4,805,000	3,994,000	5,129,000
Income (Loss) from Operations									75,350,000	81,007,000	49,895,000
Impairment of long-lived asset									1,094,000
Significant non-cash charges									4,464,000	2,645,000	1,718,000
Income tax expense (benefit)									25,348,000	28,712,000	16,146,000
Capital expenditures and acquisitions									72,291,000	26,305,000	3,816,000
Total Assets	540,082,000				557,762,000				540,082,000	557,762,000	496,970,000
North America | Continuing Operations
Segment Information
Depreciation and amortization									13,194,000	13,588,000	17,062,000
Europe
Segment Information
Net sales									118,246,000	101,314,000	93,616,000
Sales to Other Segments									575,000	136,000	282,000
Income (Loss) from Operations									1,296,000	(3,674,000)	(12,050,000)
Impairment of Goodwill									1,282,000	6,292,000
Impairment of long-lived asset										419,000
Significant non-cash charges									966,000	390,000	307,000
Income tax expense (benefit)									2,588,000	2,440,000	(364,000)
Capital expenditures and acquisitions									5,062,000	6,370,000	30,372,000
Total Assets	180,016,000				123,669,000				180,016,000	123,669,000	133,676,000
Europe | Continuing Operations
Segment Information
Depreciation and amortization									4,849,000	4,626,000	5,203,000
Asia/Pacific
Segment Information
Net sales									9,528,000	9,232,000	5,500,000
Sales to Other Segments									11,359,000	9,140,000	2,274,000
Income (Loss) from Operations									(1,471,000)	(111,000)	(4,013,000)
Significant non-cash charges									129,000	47,000	12,000
Income tax expense (benefit)									(805,000)	289,000	(152,000)
Capital expenditures and acquisitions									544,000	512,000	3,673,000
Total Assets	29,306,000				25,576,000				29,306,000	25,576,000	20,150,000
Asia/Pacific | Continuing Operations
Segment Information
Depreciation and amortization									1,211,000	1,233,000	972,000
Administrative and all other
Segment Information
Net sales									950,000	319,000
Income (Loss) from Operations									(1,118,000)	1,202,000	(2,336,000)
Significant non-cash charges									1,278,000	607,000	115,000
Income tax expense (benefit)									755,000	1,798,000	1,726,000
Capital expenditures and acquisitions									19,000	368,000	1,626,000
Total Assets	86,683,000				167,702,000				86,683,000	167,702,000	193,009,000
Assets of discontinued operations included in Administrative and all other segment											71,600,000
Capital expenditures and acquisitions from the discontinued operations											400,000
Cash and short-term investments	68,500,000				274,600,000				68,500,000	274,600,000	205,100,000
Administrative and all other | Continuing Operations
Segment Information
Depreciation and amortization									$ 1,497,000	$ 1,704,000	$ 2,127,000