Basis of Presentation (Details Textual) (USD $) In Thousands, except Share data, unless otherwise specified	1 Months Ended	3 Months Ended
Dec. 31, 2011	Mar. 31, 2012	Mar. 31, 2011	Mar. 31, 2011 Correction [Member]	Dec. 31, 2007 Correction [Member]
Basis of Presentation (Textual)
Increase to current deferred income tax assets	$ 43,032	$ 43,394	$ 57,993	$ 910	$ 910
Increase to prepaid income taxes	21,598	24,574	25,035	735	735
Increase to current taxes payable	167,560	211,286	209,662	16,676	16,676
Decrease to noncurrent deferred income tax liabilities	732,528	704,166	807,029	(5,849)	(5,849)
Decrease to retained earnings	1,334,476	1,281,080	1,416,486	(9,182)	(9,182)
Fixed exchange ratio of shares	0.50
Legal, professional and other costs incurred in response to unsolicited tender offer		$ 10,065	$ 0

The current portion of the aggregate tax effects as of the balance sheet date of all future tax deductions arising from temporary differences between tax basis and generally accepted accounting principles basis recognition of assets, liabilities, revenues and expenses, which can only be deducted for tax purposes when permitted under enacted tax laws; after deducting the allocated valuation allowance, if any, to reduce such amount to net realizable value. Deferred tax liabilities and assets are classified as current or noncurrent based on the classification of the related asset or liability for financial reporting. A deferred tax liability or asset that is not related to an asset or liability for financial reporting, including deferred tax assets related to carryforwards, are classified according to the expected reversal date of the temporary difference. An unrecognized tax benefit that is directly related to a position taken in a tax year that results in a net operating loss carryforward is presented as a reduction of the related deferred tax asset.

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Represents the noncurrent portion of deferred tax liabilities, which result from applying the applicable tax rate to net taxable temporary differences pertaining to each jurisdiction to which the entity is obligated to pay income tax. A noncurrent taxable temporary difference is a difference between the tax basis and the carrying amount of a noncurrent asset or liability in the financial statements prepared in accordance with generally accepted accounting principles. In a classified statement of financial position, an enterprise separates deferred tax liabilities and assets into a current amount and a noncurrent amount. Deferred tax liabilities and assets are classified as current or noncurrent based on the classification of the related asset or liability for financial reporting. A deferred tax liability or asset that is not related to an asset or liability for financial reporting, including deferred tax assets related to carryforwards, are classified according to the expected reversal date of the temporary difference.

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- Definition

Aggregate carrying amount, as of the balance sheet date, of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered and of liabilities not separately disclosed in the balance sheet. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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- Definition

Sum of the amounts paid in advance for capitalized costs that will be expensed with the passage of time or the occurrence of a triggering event, and will be charged against earnings within one year or the normal operating cycle, if longer.

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