SIGNIFICANT ACCOUNTING POLICIES - AOCI (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 27, 2015	Sep. 27, 2015	Jun. 28, 2015	Mar. 29, 2015	Dec. 28, 2014	Sep. 28, 2014	Jun. 29, 2014	Mar. 30, 2014	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
Changes in accumulated other comprehensive loss
Balance at the beginning of the period				$ (416,603)				$ (304,901)	$ (416,603)	$ (304,901)
Other comprehensive income (loss) before reclassifications									(801)	(819)
Amounts reclassified from AOCL									(4,404)	(110,883)
Other comprehensive income (loss)									(5,205)	(111,702)	$ 176,415
Balance at the end of the period	$ (421,808)				$ (416,603)				(421,808)	(416,603)	(304,901)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Compensation									395,449	411,881	422,981
Provision for income taxes									(11,797)	231,230	11,659
Net of tax	(8,830)	$ 1,149	$ 296,497	11,346	(302,642)	$ 2,760	$ (89,949)	15,842	300,162	(373,989)	(18,803)
Minimum Pension and Post-Retirement Liability
Changes in accumulated other comprehensive loss
Balance at the beginning of the period				(407,552)				(296,669)	(407,552)	(296,669)
Amounts reclassified from AOCL									(4,404)	(110,883)
Other comprehensive income (loss)									(4,404)	(110,883)
Balance at the end of the period	(411,956)				(407,552)				(411,956)	(407,552)	(296,669)
Minimum Pension and Post-Retirement Liability | Amount Reclassified from AOCI
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Compensation									(7,340)	(184,805)
Provision for income taxes									2,936	73,922
Net of tax									(4,404)	(110,883)
Other Comprehensive Loss Related to Equity Investments
Changes in accumulated other comprehensive loss
Balance at the beginning of the period				$ (9,051)				$ (8,232)	(9,051)	(8,232)
Other comprehensive income (loss) before reclassifications									(801)	(819)
Other comprehensive income (loss)									(801)	(819)
Balance at the end of the period	$ (9,852)				$ (9,051)				$ (9,852)	$ (9,051)	$ (8,232)