Quarterly report pursuant to Section 13 or 15(d)

Financial Instruments - Schedule of Interest Rate Derivatives (Details)

v2.4.0.8
Financial Instruments - Schedule of Interest Rate Derivatives (Details) (USD $)
Mar. 31, 2014
Dec. 31, 2013
Derivatives, Fair Value [Line Items]    
Collateral Already Posted, Aggregate Fair Value $ 500,000 $ 900,000
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member] | Other Current Liabilities [Member]
   
Derivatives, Fair Value [Line Items]    
Interest Rate Derivative Liabilities, at Fair Value (19,544,000) (13,484,000)
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member] | Noncurrent Derivative Assets [Member]
   
Derivatives, Fair Value [Line Items]    
Interest Rate Derivative Assets, at Fair Value $ 71,170,000 $ 98,123,000