SIGNIFICANT ACCOUNTING POLICIES - AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 26, 2016	Jun. 28, 2015	Jun. 26, 2016	Jun. 28, 2015
Changes in accumulated other comprehensive loss
Balance at the beginning of the period			$ (421,808)
Other comprehensive income (loss) before reclassifications			(118)
Amounts reclassified from AOCL			4,604
Other comprehensive income (loss)	$ 2,679	$ 2,750	4,486	$ 5,384
Balance at the end of the period	(417,322)		(417,322)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Compensation	98,237	101,091	201,011	207,763
Provision for income taxes	(4,731)	(3,500)	(14,846)	(11,153)
Net of tax	14,734	296,497	27,475	307,843
Minimum Pension and Post-Retirement Liability
Changes in accumulated other comprehensive loss
Balance at the beginning of the period			(411,956)
Amounts reclassified from AOCL			4,604
Other comprehensive income (loss)			4,604
Balance at the end of the period	(407,352)		(407,352)
Minimum Pension and Post-Retirement Liability | Amount Reclassified from AOCI
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Compensation	3,837	4,805	7,674	9,606
Provision for income taxes	(1,535)	(1,922)	(3,070)	(3,842)
Net of tax	2,302	$ 2,883	4,604	$ 5,764
Other Comprehensive Loss Related to Equity Investments
Changes in accumulated other comprehensive loss
Balance at the beginning of the period			(9,852)
Other comprehensive income (loss) before reclassifications			(118)
Other comprehensive income (loss)			(118)
Balance at the end of the period	$ (9,970)		$ (9,970)