Schedule Of Noncash Investing and Financing Activities (Detail) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Supplemental Cash Flow Elements [Abstract]
Accrued liabilities for purchases of property, plant and equipment	$ 20,339	$ 24,453
Acquisition of assets through capital lease	196	$ 998
Settlement of royalty obligation via asset sale	$ 900