Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common stock [Member]	Additional paid-in capital [Member]	Accumulated other comprehensive (loss) income [Member]	(Accumulated deficit) retained earnings [Member]	Treasury stock [Member]
Stockholders' equity, beginning balance at Dec. 27, 2015	$ 647,073	$ 445	$ 605,033	$ (3,158)	$ 44,753	$ 0
Shares, beginning balance at Dec. 27, 2015		44,710,497				0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	31,641				31,641
Restricted share grants	225		225
Restricted share grants (in shares)		207,729
Net actuarial gain (loss) and prior service cost, net of income taxes of $0	(819)			(819)
Non-cash compensation expense	2,442		2,442
Issuance of common stock, net of underwriters' discount	134,929	$ 86	134,843
Issuance of common stock, net of underwriters' discount (in shares)		8,625,000
Purchase of treasury stock	(417)					$ (417)
Restricted share forfeiture	0					$ 0
Restricted share forfeiture (in shares)						19,689
Repurchase of common stock	0
Purchase of treasury stock (in shares)						26,749
Common stock cash dividend	(60,101)		0		(60,101)
Shares, ending balance at Dec. 25, 2016		53,543,226				46,438
Stockholders' equity, ending balance at Dec. 25, 2016	754,973	$ 531	742,543	(3,977)	16,293	$ (417)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	(915)				(915)
Restricted share grants	225	$ 7	218
Restricted share grants (in shares)		202,758
Net actuarial gain (loss) and prior service cost, net of income taxes of $0	(1,484)			(1,484)
Non-cash compensation expense	3,135		3,135
Offering costs	$ (111)		(111)
Exercise of stock options (in shares)	92,751	12,989
Exercise of stock options	$ 0	$ 0
Purchase of treasury stock	(664)					(664)
Restricted share forfeiture	0					$ 0
Restricted share forfeiture (in shares)						50,530
Repurchased common stock, shares		(391,120)
Repurchase of common stock	(5,001)	$ (4)	(4,997)
Purchase of treasury stock (in shares)						44,004
Common stock cash dividend	$ (75,765)		(57,620)		(18,145)
Common stock (in shares) at Dec. 31, 2017	53,367,853
Shares, ending balance at Dec. 31, 2017		53,367,853				140,972
Stockholders' equity, ending balance at Dec. 31, 2017	$ 674,393	$ 534	683,168	(5,461)	(2,767)	$ (1,081)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net (loss) income	18,196				18,196
Restricted share grants	225	$ 2	223
Restricted share grants (in shares)		240,396
Net actuarial gain (loss) and prior service cost, net of income taxes of $0	(1,420)			(1,420)
Non-cash compensation expense	3,156		3,156
Issuance of common stock, net of underwriters' discount	110,719	$ 69	110,650
Issuance of common stock, net of underwriters' discount (in shares)		6,900,000
Purchase of treasury stock	(792)					(792)
Restricted share forfeiture	0					$ 0
Restricted share forfeiture (in shares)						14,754
Repurchase of common stock	0
Purchase of treasury stock (in shares)						46,237
Common stock cash dividend	$ (87,254)		(75,592)		(11,662)
Common stock (in shares) at Dec. 30, 2018	60,508,249
Shares, ending balance at Dec. 30, 2018		60,508,249				201,963
Stockholders' equity, ending balance at Dec. 30, 2018	$ 717,223	$ 605	$ 721,605	$ (6,881)	$ 3,767	$ (1,873)