Earnings Per Share - Reconciliation of Net Income Per Common Share (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 28, 2018	Jun. 29, 2018	Mar. 30, 2018	Sep. 29, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 28, 2018	Sep. 29, 2017
Numerator:
Net income	$ 4,157	$ 6,819	$ 544	$ 2,851	$ 3,674	$ (1,642)	$ 11,520	$ 4,883
Add effect of dilutive securities:
Interest on convertible notes, net of tax	26			134			358	0
Net income available to common shareholders	$ 4,183			$ 2,985			$ 11,878	$ 4,883
Denominator:
Weighted average basic common shares outstanding (in shares)	29,080,929			26,092,387			28,458,972	26,011,913
Dilutive effect of unvested common shares (in shares)	313,229			57,858			221,411	51,742
Dilutive effect of convertible notes (in shares)	349,693			1,237,374			939,320	0
Weighted average diluted common shares outstanding (in shares)	29,743,851			27,387,619			29,619,703	26,063,655

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible debt securities using the if-converted method.

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The after-tax amount of interest recognized in the period associated with any convertible debt.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities, and addition from assumption of issuance of common shares for dilutive potential common shares; of income (loss) available to common shareholders.

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