Benefit Plans - Components of Pension Benefit Cost (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Defined Benefit Plan Net Periodic Benefit Cost [Abstract]
Interest cost		$ 56,000		$ 182,000
Expected return on plan assets		(82,000)		(246,000)
Amortization of net loss				43,000
Settlement costs				97,000
Net periodic benefit cost	$ 0	$ (26,000)	$ 0	$ 76,000