Pension Benefits - Net Periodic Pension Cost (Details) $ in Thousands		1 Months Ended	3 Months Ended			9 Months Ended
	Oct. 20, 2017 USD ($)	Jul. 29, 2016 USD ($)	Sep. 24, 2017 USD ($)	Sep. 25, 2016 USD ($)	Jun. 26, 2016 USD ($)	Sep. 24, 2017 USD ($) plan	Sep. 25, 2016 USD ($)
Pension Benefits
Number of joint Company and Guild-sponsored defined benefit plans | plan						2
Litigation Settlement, Amount Awarded from Other Party				$ 5,000
Multiemployer pension plan withdrawal expense		$ 5,000	$ 0	(4,971)	$ 11,700	$ 0	$ 6,730
Pension Plan
Pension Benefits
Service cost			2,423	2,248		7,269	6,743
Interest cost			17,552	18,607		52,652	55,822
Expected return on plan assets			(26,136)	(27,790)		(78,408)	(83,369)
Amortization of actuarial loss			8,439	8,123		25,321	24,366
Amortization of prior service credit			(486)	(487)		(1,458)	(1,459)
Net periodic postretirement benefit income			1,792	701		5,376	2,103
Qualified Plans | Pension Plan
Pension Benefits
Service cost			2,423	2,248		7,269	6,743
Interest cost			15,596	16,573		46,784	49,720
Expected return on plan assets			(26,136)	(27,790)		(78,408)	(83,369)
Amortization of actuarial loss			7,351	7,069		22,057	21,206
Amortization of prior service credit			(486)	(487)		(1,458)	(1,459)
Net periodic postretirement benefit income			(1,252)	(2,387)		(3,756)	(7,159)
Pension contributions						5,900	6,000
Non- Qualified Plans | Pension Plan
Pension Benefits
Service cost			0	0		0	0
Interest cost			1,956	2,034		5,868	6,102
Expected return on plan assets			0	0		0	0
Amortization of actuarial loss			1,088	1,054		3,264	3,160
Amortization of prior service credit			0	0		0	0
Net periodic postretirement benefit income			$ 3,044	$ 3,088		$ 9,132	$ 9,262
Subsequent Event | Pension Plan
Pension Benefits
Expected contributions in 2017	$ 100,000