Financial Instruments (Details 4) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Interest rate products [Member]
Company's derivative instruments on net loss
Derivative Instruments, (Loss) Gain Recognized in OCI, Effective Portion	$ 1.3	$ (1.6)
Interest expense [Member]
Company's derivative instruments on net loss
Derivative Instruments, (Loss) Gain Reclassified from Accumulated OCI into (Income) Loss, Effective Portion	$ (0.1)