Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments (Summary of Gain or Loss on Effective Swaps Recognized in Other Comprehensive Income) (Details)

 v2.3.0.11
Derivative Instruments (Summary of Gain or Loss on Effective Swaps Recognized in Other Comprehensive Income) (Details) (Interest Rate Swap [Member], Cash Flow Hedging [Member], USD $)
In Millions
3 Months Ended 6 Months Ended
Jun. 30, 2011
Jun. 30, 2010
Jun. 30, 2011
Jun. 30, 2010
Interest Rate Swap [Member] | Cash Flow Hedging [Member]
       
Change in other comprehensive income (loss) $ 0.4 $ 0.1 $ 0.8 $ (0.2)