Employee Benefit Plans - Schedule of Net Periodic Benefit Cost (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Compensation And Retirement Disclosure [Abstract]
Benefit cost, Interest cost	$ 435	$ 494	$ 1,305	$ 1,480
Benefit cost, Expected return on plan assets	(551)	(587)	(1,652)	(1,760)
Benefit cost, Recognized actuarial loss	580	1,007	1,739	3,020
Benefit cost, Settlement cost	269		692
Total net periodic benefit cost	$ 733	$ 914	$ 2,084	$ 2,740