Restructuring, Asset Impairment Charges and Other Items - Summary of Significant Activity Within and Components of Restructuring Obligations (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2012
Lease and Contract Terminations [Member]
Restructuring Expense And Other Items Net [Line Items]
Restructuring and Related Activities, Completion Date	Dec. 31, 2014
Employee Severance and Benefits [Member]
Restructuring Expense And Other Items Net [Line Items]
Restructuring and Related Activities, Completion Date	Mar. 31, 2013