Derivative Instruments and Hedging Activities Disclosure (Details 2) (USD $) In Thousands	Jun. 30, 2011	Dec. 31, 2010
Assets and liabilities measured at fair value on a recurring basis
Total Derivative (Assets) Liabilities	$ 6,983	$ 3,977
Quoted Prices in Active Markets for Identical Assets Level 1 [Member]
Assets and liabilities measured at fair value on a recurring basis
Total Derivative (Assets) Liabilities	0	0
Significant Other Observable Inputs Level 2 [Member]
Assets and liabilities measured at fair value on a recurring basis
Total Derivative (Assets) Liabilities	6,983	3,977
Significant Unobservable Inputs Level 3 [Member]
Assets and liabilities measured at fair value on a recurring basis
Total Derivative (Assets) Liabilities	$ 0	$ 0