Financial Instruments - Changes in Fair Value of De-Designated Interest Rate Derivatives (Details) (Not Designated as Hedging Instrument [Member], Interest Rate Contract [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Not Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net	$ 101,263	$ 0	$ 83,279	$ 0