Restructuring Program - Schedule of Restructuring Program Activity (Detail) - Severance and Other Employment Expenses [Member] - 2016 Restructuring Programs [Member] $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($)
Restructuring Cost And Reserve [Line Items]
Liability, beginning balance	$ 7,842
Reduction in estimated expenses	(572)
Payments made	(6,941)
Liability, ending balance	$ 329