Property, Plant and Equipment - Additional Information (Detail) - USD ($) $ in Thousands	Apr. 01, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 8,310,000	$ 8,160,000
Property, plant and equipment, net	5,133,404	5,078,650
Group Of Wells Assets With Carrying Value Closest To Its Undiscounted Cash Flows [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 78,400	$ 80,800