Inventories, Net and Significant Suppliers - Related Party Supplier (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Executive Vice President
Related Party Transactions [Line Items]
Ownership percentage in third party by executive	40.00%
Inventory Purchases \| Supplier Concentration Risk \| Affiliated Entity
Related Party Transactions [Line Items]
Inventory purchases form related party	$ 5,217	$ 6,350	$ 8,550
Concentration risk percentage	1.20%	1.80%	2.50%
Accounts Payable \| Supplier Concentration Risk \| Affiliated Entity
Related Party Transactions [Line Items]
Accounts payable, related parties	$ 1,500	$ 1,690
Concentration risk percentage	1.30%	1.70%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 18
-URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6351-108592

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13531-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 275
-SubTopic 10
-Section 50
-Paragraph 20
-URI http://asc.fasb.org/extlink&oid=84177426&loc=d3e6404-108592

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 21
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13537-108611

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration