Shares Repurchased Under Stock Repurchase Plan (Detail) - USD ($) $ in Thousands	3 Months Ended	4 Months Ended	12 Months Ended	180 Months Ended
	Jul. 15, 2017	Apr. 22, 2017	Dec. 30, 2017	Dec. 30, 2017
Equity [Abstract]
Total Number of Shares Purchased	28,050	112,085	140,135	67,900
Total Cost of Shares Purchased	$ 520	$ 2,151	$ 2,671	$ 633,100