Components of Income Tax Expense (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation of Statutory Tax Rate [Line Items]
Tax at US statutory rate of 35%	$ (123,039)	$ (445,922)	$ (56,582)
Tax rate differences	43,142	201,837	22,293
Valuation allowance	13,538	61,293	29,675
Permanent differences	86,906	220,304	(9,247)
Other	(8,850)	0	0
Income tax (benefit)/expense	$ 11,697	$ 37,512	$ (13,861)

The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing operations.

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The portion of the difference between total income tax expense or benefit as reported in the Income Statement and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to changes in the valuation allowance for deferred tax assets in the period.

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- Definition

The portion of the difference, between total income tax expense or benefit as reported in the Income Statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations, that is attributable to total foreign income tax expense or benefit. The foreign income tax expense or benefit difference represents the income tax expense or benefit at applicable domestic statutory income tax rates applied to foreign earnings or loss for the period versus the foreign income tax expense or benefit calculated by applying the appropriate foreign tax rates.

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- Definition

The amount of income tax expense or benefit for the period computed by applying the domestic federal statutory tax rates to pretax income from continuing operations.

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