Acquisitions & Dispositions - Purchase Price Allocation (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill	$ 297,906	$ 299,355
CPO [Member]
Business Acquisition [Line Items]
Purchase price, net of cash acquired	32,225
Accounts receivable	(2,956)
Inventories	(13,051)
Other current assets	(269)
Property, plant and equipment, net	(488)
Intangible assets	(12,800)
Total assets acquired	(29,564)
Accounts payable	16,911
Accrued liabilities	2,580
Deferred income taxes	3,453
Other long-term liabilities	90
Total liabilities assumed	23,034
Goodwill	25,695
MEDCO [Member]
Business Acquisition [Line Items]
Purchase price, net of cash acquired	145,873
Accounts receivable	(44,815)
Inventories	(55,491)
Other current assets	(1,299)
Property, plant and equipment, net	(4,408)
Other assets	(650)
Intangible assets	(40,000)
Total assets acquired	(146,663)
Accounts payable	32,383
Accrued liabilities	5,542
Deferred income taxes	2,167
Other long-term liabilities	52
Total liabilities assumed	40,144
Goodwill	39,354
NESTOR [Member]
Business Acquisition [Line Items]
Purchase price, net of cash acquired	39,983
Accounts receivable	(9,230)
Inventories	(12,067)
Other current assets	(339)
Property, plant and equipment, net	(1,251)
Other assets	(752)
Intangible assets	(16,930)
Total assets acquired	(40,569)
Accounts payable	4,992
Accrued liabilities	1,943
Deferred income taxes	3,287
Other long-term liabilities	76
Total liabilities assumed	10,298
Goodwill	$ 9,712