Leases (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011
Minimum Lease Payments
2012, Operating Leases	$ 84,860
2012, Capital Leases	6,494
2013, Operating Leases	78,552
2013, Capital Leases	6,494
2014, Operating Leases	78,559
2014, Capital Leases	4,694
2015, Operating Leases	62,043
2015, Capital Leases	4,615
2016, Operating Leases	37,963
2016, Capital Leases	4,457
Years thereafter, Operating Leases	166,445
Years thereafter, Capital Leases	38,025
Minimum lease payments, Operating leases	508,422
Minimum lease payments, Capital leases	64,779
Less: Amount representing interest, Operating Leases	0
Less: Amount representing interest, Capital Leases	23,621
Present value of net minimum lease payments, Operating Leases	508,422
Present value of net minimum lease payments, Capital Leases	$ 41,158

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The total of contractually required rental payments on leases meeting the criteria for capitalization.

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Amount necessary to reduce net minimum lease payments to present value calculated at the lesser of the interest rate implicit in the lease (if known) or the entity's incremental borrowing rate (as defined) at inception of the lease.

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The discounted value of future cash flows under leases meeting the criteria for capitalization.

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

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