Income Taxes - Tax Benefits of These Mexican NOL Carryforwards (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, or NOLs	$ 24,067	$ 27,212
Mexico [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, or NOLs	16,600
2013 [Member] | Mexico [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, or NOLs	100
2014 [Member] | Mexico [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, or NOLs	3,900
2015 [Member] | Mexico [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, or NOLs	4,300
2016 [Member] | Mexico [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, or NOLs	4,600
2017 [Member] | Mexico [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, or NOLs	3,200
2021 [Member] | Mexico [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss carryforwards, or NOLs	$ 500