CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY (Parenthetical) - shares	9 Months Ended
	Sep. 30, 2017	Sep. 24, 2016
Statement of Stockholders' Equity [Abstract]
Purchase of treasury shares, shares acquired (in shares)	384,622	245,789
Stock plan exercises; shares acquired (in shares)	19,086	10,747
Stock options exercised; shares issued (in shares)	84,432	62,535
Stock awards; shares issued (in shares)	5,677	6,976