Estimated Future Amortization Expense for Identifiable Intangible Assets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Expected Amortization Expense [Line Items]
Estimated amortization expense 2013	$ 135,308
Estimated amortization expense 2014	113,848
Estimated amortization expense 2015	113,559
Estimated amortization expense 2016	112,770
Estimated amortization expense 2017	$ 111,625