Pensions and Other Post-retirement Benefits - Schedule of Amounts Included in Accumulated Other Comprehensive Income Expected To Be Recognized In Net Periodic Benefit Costs (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($)
Pension Benefits
Schedule of Pension and Other Postretirement Benefits Recognized in Accumulated Other Comprehensive Income (Loss) [Line Items]
Loss recognition	$ 12,255
Prior service credit recognition	(15)
Transition obligation recognition	1
Other Benefits
Schedule of Pension and Other Postretirement Benefits Recognized in Accumulated Other Comprehensive Income (Loss) [Line Items]
Loss recognition	103
Prior service credit recognition	(288)
Transition obligation recognition	$ 0