Benefit Plans - Schedule of Pension Plan Weighted-Average Asset Allocations by Asset Category (Detail)	Dec. 29, 2012	Dec. 31, 2011
U.K. Plan [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	59.00%	58.30%
U.K. Plan [Member] | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	40.60%	41.70%
U.K. Plan [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	0.40%	0.00%
U.S. Plan [Member] | Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	65.20%	66.90%
U.S. Plan [Member] | Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	32.40%	33.10%
U.S. Plan [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Weighted-average asset allocations	2.30%	0.00%