Net Deferred Tax Assets and Liabilities (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Schedule of Deferred Income Tax Assets and Liabilities [Line Items]
Total deferred tax assets	$ 76,193	$ 76,432
Total deferred tax liabilities	(140,237)	(150,614)
Net deferred income tax liabilities	$ (64,044)	$ (74,182)

For entities that net deferred tax assets and tax liabilities, represents the unclassified net amount of deferred tax assets and liabilities as of the balance sheet date, which result from applying the applicable enacted tax rate to net temporary differences and carryforwards pertaining to assets or liabilities. A temporary difference is a difference between the tax basis of an asset or liability and its carrying amount in the financial statements prepared in accordance with generally accepted accounting principles that will reverse in ensuing periods.

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The cumulative amount of all 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 taxable temporary difference is a difference between the tax basis and the carrying amount of an asset or liability in the financial statements prepared in accordance with generally accepted accounting principles that will result in taxable amounts in one or more future periods.

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