Segment Information and Enterprise-wide Disclosures (Revenue by Customer locations) (Details) (USD $)
In Thousands, unless otherwise specified

3 Months Ended

12 Months Ended

Dec. 31, 2012

Sep. 30, 2012

Jun. 30, 2012

Mar. 31, 2012

Dec. 31, 2011

Sep. 30, 2011

Jun. 30, 2011

Mar. 31, 2011

Dec. 31, 2012

Dec. 31, 2011

Dec. 31, 2010

Segment Reporting, Revenue Reconciling Item [Line Items]

NET SALES

$ 163,287

$ 166,617

$ 159,239

$ 144,663

$ 143,313

$ 160,577

$ 169,806

$ 161,555

$ 633,806

$ 635,251

$ 612,886

Sales Revenue Net Percentage

100.00%

China [Member]

Segment Reporting, Revenue Reconciling Item [Line Items]

NET SALES

223,473

206,965

187,633

Sales Revenue Net Percentage

35.00%

33.00%

31.00%

Taiwan [Member]

Segment Reporting, Revenue Reconciling Item [Line Items]

NET SALES

126,356

136,129

141,388

Sales Revenue Net Percentage

20.00%

21.00%

23.00%

United States [Member]

Segment Reporting, Revenue Reconciling Item [Line Items]

NET SALES

54,949

47,892

76,328

Sales Revenue Net Percentage

9.00%

8.00%

12.00%

Switzerland [Member]

Segment Reporting, Revenue Reconciling Item [Line Items]

NET SALES

57,200

57,696

58,583

Sales Revenue Net Percentage

9.00%

8.00%

10.00%

Korea [Member]

Segment Reporting, Revenue Reconciling Item [Line Items]

NET SALES

50,896

37,643

35,180

Sales Revenue Net Percentage

8.00%

6.00%

Germany [Member]

Segment Reporting, Revenue Reconciling Item [Line Items]

NET SALES

24,416

30,838

31,704

Sales Revenue Net Percentage

4.00%

5.00%

Singapore [Member]

Segment Reporting, Revenue Reconciling Item [Line Items]

NET SALES

27,013

23,492

24,468

Sales Revenue Net Percentage

4.00%

UK [Member]

Segment Reporting, Revenue Reconciling Item [Line Items]

NET SALES

28,558

30,065

24,337

Sales Revenue Net Percentage

5.00%

4.00%

All Others [Member]

Segment Reporting, Revenue Reconciling Item [Line Items]

NET SALES

$ 40,945

$ 64,531

$ 33,265

Sales Revenue Net Percentage

6.00%

10.00%

5.00%