SIGNIFICANT ACCOUNTING POLICIES - AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 25, 2016	Sep. 27, 2015	Sep. 25, 2016	Sep. 27, 2015
Changes in accumulated other comprehensive loss
Balance at the beginning of the period			$ (421,808)
Other comprehensive income (loss) before reclassifications			(937)
Amounts reclassified from AOCL			6,907
Other comprehensive income (loss)	$ 1,484	$ 2,689	5,970	$ 8,073
Balance at the end of the period	(415,838)		(415,838)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Compensation	95,045	95,015	296,056	302,778
Provision for income taxes	(5,885)	(4,882)	(20,731)	(16,035)
Net of tax	9,804	1,149	37,279	308,992
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			6,907
Other comprehensive income (loss)			6,907
Balance at the end of the period	(405,049)		(405,049)
Minimum Pension and Post-Retirement Liability | Amount Reclassified from AOCI
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Compensation	3,838	4,802	11,511	14,408
Provision for income taxes	(1,535)	(1,921)	(4,604)	(5,763)
Net of tax	2,303	$ 2,881	6,907	$ 8,645
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			(937)
Other comprehensive income (loss)			(937)
Balance at the end of the period	$ (10,789)		$ (10,789)