Annual report pursuant to Section 13 and 15(d)

套期保值活动(财务状况表衍生工具一览表)(详情)

v2.4.0.6
套期保值活动(财务状况表衍生工具表)(详情)(美元)
Dec. 31, 2011
Dec. 31, 2010
Hedging Activities [Abstract]    
Short-term derivative instruments - asset $ 1,601,000  
Short-term derivative instruments - liabilities   $ 4,720,000