Income Taxes (Detail) - Current and Long-Term Deferred Tax Assets and Liabilities (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Expense accruals	$ 49,404	$ 40,438
Loss and credit carryforwards	22,433	24,282
Assets relating to equity compensation	18,878	18,226
Other assets	7,613	8,949
Gross deferred tax asset	98,328	91,895
Depreciation	(8,995)	(9,199)
Intangible assets	(23,129)	(17,024)
Prepaid expenses	(10,500)	(10,183)
Gross deferred tax liability	(42,624)	(36,406)
Valuation allowance	(1,943)	(1,869)
Net deferred tax asset	$ 53,761	$ 53,620