CONDENSED CONSOLIDATED STATEMENT OF SHAREHOLDERS' EQUITY (Unaudited) - 4 months ended Apr. 22, 2017 - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]
Balance, value at Dec. 31, 2016	$ 825,407	$ 521,984	$ (11,437)	$ 314,860
Balance, shares at Dec. 31, 2016	37,539	37,539
Net earnings	$ 15,025			15,025
Other comprehensive income	25		25
Dividends - $0.165 per share	(6,255)			(6,255)
Stock-based employee compensation	6,352	$ 6,352
Issuances of common stock on stock option exercises and stock bonus plan, value	3,506	$ 3,506
Issuances of common stock on stock option exercises and stock bonus plan, share		165
Issuances of restricted stock, shares		271
Cancellations of stock-based awards, value	(2,607)	$ (2,607)
Cancellations of stock-based awards, shares		(115)
Balance, value at Apr. 22, 2017	$ 841,453	$ 529,235	$ (11,412)	$ 323,630
Balance, shares at Apr. 22, 2017	37,860	37,860