Valuation and Qualifying Accounts (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for obsolete inventory
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 45,175	$ 36,269	$ 26,171
Additions Charged to Costs and Expenses	36,150	19,770	21,648
Additions Through Acquisition	0	5,165	1,942
Other Changes Add (Deduct)	(34,206)	(16,029)	(13,492)
Balance at End of Period	47,119	45,175	36,269
Allowance for doubtful accounts receivable
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	19,439	8,644	7,424
Additions Charged to Costs and Expenses	(965)	7,085	2,169
Additions Through Acquisition	0	4,644	59
Other Changes Add (Deduct)	(7,560)	(934)	(1,008)
Balance at End of Period	$ 10,914	$ 19,439	$ 8,644