Restructuring - Summary of Restructuring Plan Activity (Detail) $ in Thousands	6 Months Ended
	Jun. 30, 2017 USD ($)
Q2 2017 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring liability, Beginning balance	$ 0
Restructuring expense and adjustments	1,273
Cash payments	(1,148)
Restructuring liability, Ending balance	125
Cumulative costs to date, as of June 30, 2017	1,273
Total costs expected to be incurred, as of June 30, 2017	1,429
Q2 2015 Restructuring Plan [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring liability, Beginning balance	19,388
Restructuring expense and adjustments	(676)
Cash payments	(2,772)
Restructuring liability, Ending balance	15,940
Cumulative costs to date, as of June 30, 2017	34,099
Total costs expected to be incurred, as of June 30, 2017	$ 34,099