Stock Compensation Plan - Restricted Stock Unit Activity (Parenthetical) (Detail)	0 Months Ended						12 Months Ended
	Jul. 02, 2012	Jan. 10, 2012	Jan. 02, 2012	Jul. 02, 2011	Jan. 02, 2011	Jan. 10, 2011	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Treasury stock authorized to satisfy minimum statutory tax withholding requirements (shares)	3,953	79,035	594	4,121	52,138	82,174	83,582	138,433
Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Treasury stock authorized to satisfy minimum statutory tax withholding requirements (shares)							0	0
Treasury Stock | Class A Common Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Treasury stock authorized to satisfy minimum statutory tax withholding requirements (shares)							83,582	138,433