Shareholders' Equity and Accumulated Other Comprehensive Income Changes in Shareholders' Equity (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 27, 2014	Jun. 28, 2013	Jun. 27, 2014	Jun. 28, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning Balance			$ 511,292	$ 420,193
Comprehensive Income	19,001	19,296	30,896	23,300
Dividends declared			(8,652)	(8,549)
Employee stock plans and related tax benefit			4,639	2,654
Purchase of treasury shares			(843)	(644)
Allocated Share-based Compensation Expense	2,000	1,900	3,293	3,065
Ending Balance	$ 540,625	$ 440,019	$ 540,625	$ 440,019

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Glossary Other Comprehensive Income

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-Name Accounting Standards Codification

-Topic 220

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-Glossary Net Income

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Amount of paid and unpaid cash, stock, and paid-in-kind (PIK) dividends declared, for example, but not limited to, common and preferred stock.

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-Publisher SEC

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The total cash inflow associated with the amount received from holders to acquire the entity's shares under incentive and share awards, including stock option exercises. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Glossary Financing Activities

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

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