Components of Net Periodic Pension Expense (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,890		$ 1,875		$ 1,465
Interest cost	1,010		840		742
Expected return on plan assets	(125)
Recognition of actuarial gain	(135)		(350)		(200)
Recognition of termination benefits	65		65		192
Net periodic pension expense	$ 2,705	[1]	$ 2,430	[1]	$ 2,199	[1]

[1] Pension expense is classified in SG&A in the Consolidated Statements of Operations.