Inventories - Changes in Inventory Reserve (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Inventory Disclosure [Abstract]
Beginning balance	$ (47,488)us-gaap_InventoryValuationReserves	$ (72,400)us-gaap_InventoryValuationReserves
Change in reserve	(896)mx_InventoryValuationReservesChanges	(2,788)mx_InventoryValuationReservesChanges
Write off	6,338us-gaap_InventoryWriteDown	4,012us-gaap_InventoryWriteDown
Translation adjustments	228	911
Ending balance	$ (41,818)us-gaap_InventoryValuationReserves	$ (70,265)us-gaap_InventoryValuationReserves

Amount of valuation reserve for inventory.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.6(a))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 330

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SAB TOPIC 5.BB)

-URI http://asc.fasb.org/extlink&oid=27011343&loc=d3e100047-122729

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 235

-SubTopic 10

-Section S99

-Paragraph 4

-Subparagraph (SX 210.12-09)

-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 330

-SubTopic 10

-Section 35

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=51655945&loc=d3e3927-108312

Name:	us-gaap_InventoryValuationReserves
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant