Employee Benefit Plans (Defined Benefit Pension Plans not Recognized as Component of Combined Net Period Benefit Cost) (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]
Amounts included in accumulated other comprehensive loss, net of tax	$ 6,113	$ 14,601	$ 577
Not Recognized As Combined Net Period Benefit Cost [Member]
Defined Benefit Plan Disclosure [Line Items]
Net actuarial loss	(75,494)	(66,287)
Deferred tax benefit	26,423	23,200
Amounts included in accumulated other comprehensive loss, net of tax	$ (49,071)	$ (43,087)