Net Income Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended				6 Months Ended
	Sep. 29, 2018	Jun. 30, 2018	Sep. 30, 2017	Jul. 01, 2017	Sep. 29, 2018	Sep. 30, 2017
Net income per common share:
Net income	$ 30,111	$ 27,467	$ 14,823	$ 21,809	$ 57,578	$ 36,632
Denominator:
Denominator for basic net income per common share-weighted-average shares outstanding	24,325,754		23,946,360		24,233,266	23,875,749
Effect of dilution due to employee stock options	393,302		363,233		401,880	374,991
Denominator for diluted net income per common share - weighted-average shares outstanding	24,719,056		24,309,593		24,635,146	24,250,740
Basic net income per common share	$ 1.24		$ 0.62		$ 2.38	$ 1.53
Diluted net income per common share	$ 1.22		$ 0.61		$ 2.34	$ 1.51