Derivatives and Hedging Activities (Details 1) (Fair Value, Measurements, Recurring [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Summary of Company's liability derivatives
Fair Value	$ 16,832	$ 8,906
Interest Rate Swap [Member]
Summary of Company's liability derivatives
Fair Value	$ 16,832	$ 8,906

Fair value as of the balance sheet date of the gross assets less the gross liabilities of a derivative liability or group of derivative liabilities.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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