Stockholders' Equity (Details) - USD ($)		3 Months Ended
		Jun. 27, 2015	Jun. 28, 2014
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, common stock, shares		8,859,199
Beginning balance		$ 320,154,000
Stock option exercises, amount		237,000
Stock-based compensation		331,000
Net income		5,385,000	$ 5,759,000
Other comprehensive loss	[1]	$ (409,000)
Ending balance, common stock, shares		8,868,684
Ending balance		$ 325,698,000
Pre-tax unrealized loss on available-for-sale investments		$ (640,000)
Common Stock
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance, common stock, shares		8,859,199
Beginning balance		$ 89,000
Stock option exercises, shares		9,485
Stock option exercises, amount		$ 0
Stock-based compensation		0
Net income		0
Other comprehensive loss		$ 0
Ending balance, common stock, shares		8,868,684
Ending balance		$ 89,000
Additional paid-in capital
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		237,916,000
Stock option exercises, amount		237,000
Stock-based compensation		331,000
Net income		0
Other comprehensive loss		0
Ending balance		238,484,000
Retained earnings
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		81,645,000
Stock option exercises, amount		0
Stock-based compensation		0
Net income		5,385,000
Other comprehensive loss		0
Ending balance		87,030,000
Accumulated other comprehensive income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		504,000
Stock option exercises, amount		0
Stock-based compensation		0
Net income		0
Other comprehensive loss	[1]	(409,000)
Ending balance		$ 95,000

[1] Other comprehensive income is comprised of unrealized gains and losses on available-for-sale investments. Unrealized losses before tax effect on available-for-sale securities were $640,000 for the three months ended June 27, 2015.