Supplemental Stockholders' Equity Information - Changes in Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended						6 Months Ended		12 Months Ended
	Jun. 30, 2013	Mar. 31, 2013	Dec. 30, 2012	Sep. 23, 2012	Jun. 24, 2012	Mar. 25, 2012	Jun. 30, 2013	Jun. 24, 2012	Dec. 30, 2012	Dec. 25, 2011
Changes in accumulated other comprehensive income (loss):
Balance, beginning of period	$ (509,938)	$ (512,567)	$ (495,184)	$ (499,375)	$ (496,702)	$ (497,058)	$ (512,567)	$ (497,058)	$ (497,058)	$ 14,500
Other comprehensive (loss)/income before reclassifications, before tax							(216)
Amounts reclassified from accumulated other comprehensive loss, before tax							13,195
Income tax (benefit)/expense	3,672	1,780	(11,492)	2,539	(1,647)	(160)	5,452	(1,807)	(10,760)	(86,065)
Other comprehensive income/(loss), net of tax	4,899	2,628	(17,382)	4,191	(2,673)	352	7,527	(2,321)	(15,512)	(124,908)
Balance, end of period	(505,040)	(509,938)	(512,567)	(495,184)	(499,375)	(496,702)	(505,040)	(499,375)	(512,567)	(497,058)
Foreign Currency Translation Adjustments [Member]
Changes in accumulated other comprehensive income (loss):
Balance, beginning of period		11,327					11,327
Other comprehensive (loss)/income before reclassifications, before tax							(1,764)
Amounts reclassified from accumulated other comprehensive loss, before tax							0
Income tax (benefit)/expense							(528)
Other comprehensive income/(loss), net of tax							(1,236)
Balance, end of period	10,091						10,091
Unrealized Loss on Available-For-Sale Security [Member]
Changes in accumulated other comprehensive income (loss):
Balance, beginning of period		(431)					(431)
Other comprehensive (loss)/income before reclassifications, before tax							(114)
Amounts reclassified from accumulated other comprehensive loss, before tax							0
Income tax (benefit)/expense							(47)
Other comprehensive income/(loss), net of tax							(67)
Balance, end of period	(498)						(498)
Funded Status of Benefit Plans [Member]
Changes in accumulated other comprehensive income (loss):
Balance, beginning of period		(523,463)					(523,463)
Other comprehensive (loss)/income before reclassifications, before tax							1,662
Amounts reclassified from accumulated other comprehensive loss, before tax							13,195
Income tax (benefit)/expense							6,027
Other comprehensive income/(loss), net of tax							8,830
Balance, end of period	$ (514,633)						$ (514,633)