Commitments - Future Minimum Annual Lease Payments Under All Leases (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011
Commitments and Contingencies Disclosure [Line Items]
Future minimum annual Lease payments due in 2012	$ 44,971
Future minimum annual Lease payments due in 2013	31,917
Future minimum annual Lease payments due in 2014	18,436
Future minimum annual Lease payments due in 2015	9,450
Future minimum annual Lease payments due in 2016	6,605
Future minimum annual Lease payments due Thereafter	7,206
Operating Leases, Future Minimum Payments Due, Total	$ 118,585

The total of future contractually required payments on leases defined as operating.

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For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within one year of the balance sheet date relating to leases defined as operating.

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- Definition

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the fifth year of the balance sheet date relating to leases defined as operating.

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- Definition

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the fourth year of the balance sheet date relating to leases defined as operating.

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- Definition

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the third year of the balance sheet date relating to leases defined as operating.

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- Definition

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due within the second year of the balance sheet date relating to leases defined as operating.

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- Definition

For leases having an initial or remaining non-cancelable letter-terms in excess of one year, required rental payments due after the fifth year from the balance sheet date on leases defined as operating.

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