Employee Benefit Plans - Components of Net Benefit Cost (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Tax charge (benefit) in plan assets and benefits obligations recognition	$ (11,805)	$ (11,495)	$ 7,530
Recognition of actuarial losses	2,167
Settlement loss	1,135
Settlement charges	$ 1,032