Employee Benefit Plans - Other Changes in Plan Assets and Benefit Obligations Recognized in Accumulated Other Comprehensive (Income) Loss (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Pension Plan, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net (gain) loss	$ (86)	$ 22
Amortization of prior service cost	0	0
Amortization of net obligation at transition	0	0
Total recognized in other comprehensive loss/(income)	(86)	22
Total recognized in net periodic benefit cost and other comprehensive loss/(income)	26	33
Other Postretirement Benefit Plan, Defined Benefit
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Net (gain) loss	(170)	(147)
Amortization of prior service cost	0	0
Amortization of net obligation at transition	0	0
Total recognized in other comprehensive loss/(income)	(170)	(147)
Total recognized in net periodic benefit cost and other comprehensive loss/(income)	$ (120)	$ (94)