Employee Benefit Plans - Schedule of Net Periodic Benefit Cost (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Compensation and Retirement Disclosure [Abstract]
Benefit Cost, Interest cost	$ 440	$ 415	$ 880	$ 830
Benefit Cost, Expected return on plan assets	(442)	(511)	(885)	(1,023)
Benefit Cost, Recognized actuarial loss	494	531	988	1,062
Benefit Cost, Settlement loss	235	196	441	402
Net periodic benefit cost	$ 727	$ 631	$ 1,424	$ 1,271