Reconciliation of Average Number of Common Shares and Common Share Equivalents Outstanding (Detail) - shares	3 Months Ended
	Mar. 31, 2018	Apr. 01, 2017
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Average number of common shares outstanding	42,038,000	41,879,000
Incremental shares from assumed exercises of stock options	60,000	119,000
Average number of common shares and common share equivalents outstanding	42,098,000	41,998,000