Employee Benefit Plans (Net Periodic Cost) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Compensation And Retirement Disclosure [Abstract]
Service costs	$ 329	$ 479	$ 658	$ 958
Interest costs	6,956	6,724	13,912	13,448
Expected return on plan assets	(4,694)	(4,674)	(9,388)	(9,348)
Amortization of net actuarial loss	7,407	8,002	14,814	16,004
Amortization of prior service credit	(1,038)	(1,096)	(2,076)	(2,192)
Net periodic cost	$ 8,960	$ 9,435	$ 17,920	$ 18,870