Computation of Earnings Per Share - Schedule of Earnings Per Share, Basic and Diluted (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
Mar. 29, 2019	Mar. 30, 2018
Earnings Per Share Reconciliation [Abstract]
Net earnings	$ 14,125	$ 14,066
Basic:
Weighted average number of shares outstanding (in shares)	27,908	27,851
Basic earnings per share (in usd per share)	$ 0.51	$ 0.51
Diluted:
Weighted average shares issuable on exercise of dilutive stock options (in shares)	162	220
Weighted average shares issuable on redemption of warrants related to the 2017 Notes (in shares)	0	97
Diluted (in shares)	28,070	28,168
Diluted earnings per share (in usd per share)	$ 0.50	$ 0.50

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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The amount of net income (loss) for the period available to each share of common stock or common unit outstanding during the reporting period and to each share or unit that would have been outstanding assuming the issuance of common shares or units for all dilutive potential common shares or units outstanding during the reporting period.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of call options and warrants using the treasury stock method.

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Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

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