Other Current Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Other Current Liabilities
Other derivative agreements (unrealized)	$ 6,056
Accrued interest	17,610	17,867
Partnership interest rate swap	927	905
Other liabilities	15,130	15,655
Total	$ 39,723	$ 34,427

Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid. 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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Carrying value as of the balance sheet date of obligations incurred through that date and payable arising from transactions not otherwise specified in the taxonomy. 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

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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