Fair Value Measurements (Details 2) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Other current assets
Fair value measurement, additional disclosure
Cash collateral deposits held by financial counterparties	$ 3,100,000	$ 22,900,000
Commodity contracts
Derivative instruments, at their respective fair value positions
Total Net Assets	31,946,000	19,654,000
Total Net Liabilities	13,988,000	16,140,000
Fair value measurement, additional disclosure
Cash collateral received from customers	300,000	6,600,000
Commodity contracts | Other current assets
Derivative instruments, at their respective fair value positions
Total Net Assets	30,146,000	18,277,000
Commodity contracts | Identifiable intangible and other non-current assets
Derivative instruments, at their respective fair value positions
Total Net Assets	1,800,000	1,377,000
Commodity contracts | Accrued expenses and other current liabilities
Derivative instruments, at their respective fair value positions
Total Net Liabilities	13,526,000	15,152,000
Commodity contracts | Other long-term liabilities
Derivative instruments, at their respective fair value positions
Total Net Liabilities	462,000	988,000
Foreign currency contracts
Derivative instruments, at their respective fair value positions
Total Net Assets	574,000	145,000
Total Net Liabilities	8,573,000	1,556,000
Foreign currency contracts | Other current assets
Derivative instruments, at their respective fair value positions
Total Net Assets	574,000	145,000
Foreign currency contracts | Accrued expenses and other current liabilities
Derivative instruments, at their respective fair value positions
Total Net Liabilities	8,485,000	1,458,000
Foreign currency contracts | Other long-term liabilities
Derivative instruments, at their respective fair value positions
Total Net Liabilities	$ 88,000	$ 98,000