Consolidated Statements of Stockholders' Equity and Redeemable Noncontrolling Interest Statement - USD ($) $ in Thousands	Total	Common Stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income
Beginning balance, common stock, shares at Mar. 28, 2015		8,859,199
Beginning balance at Mar. 28, 2015	$ 320,154	$ 89	$ 237,916	$ 81,645	$ 504
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	28,541	0	0	28,541	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(184)	0	0	0	(184)
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax	969	$ 0	0	0	969
Stock Issued During Period, Shares, New Issues		68,790
Stock option exercises and associated tax benefits, amount	1,984	$ 0	1,984	0	0
Stock-based compensation	1,762	$ 0	1,762	0	0
Ending balance, common stock, shares at Apr. 02, 2016		8,927,989
Ending balance at Apr. 02, 2016	353,226	$ 89	241,662	110,186	1,289
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	37,955	0	0	37,955	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(223)	0	0	0	(223)
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax	320	$ 0	0	0	320
Stock Issued During Period, Shares, New Issues		66,979
Stock option exercises and associated tax benefits, amount	1,005	$ 1	1,004	0	0
Stock-based compensation	$ 2,125	$ 0	2,125	0	0
Ending balance, common stock, shares at Apr. 01, 2017	8,994,968	8,994,968
Ending balance at Apr. 01, 2017	$ 394,408	$ 90	244,791	148,141	1,386
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	61,502	0	0	61,502	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	(964)	0	0	0	(964)
Available-for-sale Securities, Change in Net Unrealized Holding Gain (Loss), Net of Tax	702	$ 0	0	0	702
Stock Issued During Period, Shares, New Issues		49,890
Stock option exercises and associated tax benefits, amount	(915)	$ 0	(915)
Stock-based compensation	$ 2,321		2,321
Ending balance, common stock, shares at Mar. 31, 2018	9,044,858	9,044,858
Ending balance at Mar. 31, 2018	$ 457,106	$ 90	$ 246,197	209,381	1,438
Increase (Decrease) in Stockholders' Equity [Roll Forward]
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets | Accounting Standards Update 2016-09 [Member]	(52)			(52)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets | Accounting Standards Update 2018-02 [Domain]	$ 0			$ (314)	$ (314)