Defined Benefit Plans - Net Periodic Cost (Benefit) (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Compensation and Retirement Disclosure [Abstract]
Expected return on plan assets, net of expenses	$ (3,129)	$ (2,772)	$ (9,386)	$ (8,316)
Interest cost on projected benefit obligation	2,001	1,835	6,002	5,506
Net amortization and deferral	672	1,640	2,015	4,919
Net periodic expense (benefit)	$ (456)	$ 703	$ (1,369)	$ 2,109