Condensed Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock Including Additional Paid in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance at Dec. 31, 2017		$ 80,336	$ 161,364	$ (6,117)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised		858
Stock awards vested		2,717
Stock repurchased related to the exercise of stock options		(4,739)
Stock-based compensation		2,273
Net Income	$ 4,191		4,191
Other Comprehensive Income, Net of Tax	748			748
Ending Balance at Jun. 30, 2018	250,270	81,445	175,512	(6,687)
Beginning Balance at Mar. 31, 2018		80,635	173,921	(6,982)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised		737
Stock awards vested		410
Stock repurchased related to the exercise of stock options		(1,363)
Stock-based compensation		1,026
Net Income	1,591		1,591
Other Comprehensive Income, Net of Tax	295			295
Ending Balance at Jun. 30, 2018	250,270	81,445	175,512	(6,687)
Beginning Balance at Dec. 31, 2018	256,825	83,826	180,356	(7,357)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised		839
Stock awards vested		6,635
Stock repurchased related to the exercise of stock options		(10,612)
Stock-based compensation		3,271
Net Income	15,287		15,287
Other Comprehensive Income, Net of Tax	249			249
Ending Balance at Jun. 29, 2019	272,230	83,959	195,379	(7,108)
Beginning Balance at Mar. 30, 2019		83,485	187,564	(7,271)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised		742
Stock awards vested		2,339
Stock repurchased related to the exercise of stock options		(4,414)
Stock-based compensation		1,807
Net Income	7,815		7,815
Other Comprehensive Income, Net of Tax	163			163
Ending Balance at Jun. 29, 2019	$ 272,230	$ 83,959	$ 195,379	$ (7,108)