Share Based Compensation (Details Textual) (USD $) In Millions, except Share data	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Share Based Compensation (Textuals) [Abstract]
Total share-based compensation	$ 2.4	$ 1.6	$ 4.9	$ 3.4
Total share-based compensation after tax	$ 1.5	$ 1.0	$ 3.1	$ 2.1
Vesting period for the 2011 SAR grant			3 years
Portion of an award vesting for the 2011 SAR grant			1/3 vesting after each year
Stock Appreciation Rights (SARs) [Member]
Additional Share Based Compensation (Textuals) [Abstract]
Share-based compensation arrangement by share-based payment award, equity instruments other than options, Grants in period			416,700
Restricted Stock [Member]
Additional Share Based Compensation (Textuals) [Abstract]
Share-based compensation arrangement by share-based payment award, equity instruments other than options, Grants in period			200,366
Performance Shares [Member]
Additional Share Based Compensation (Textuals) [Abstract]
Share-based compensation arrangement by share-based payment award, equity instruments other than options, Grants in period			87,570
Phantom Stock Units [Member]
Additional Share Based Compensation (Textuals) [Abstract]
Share-based compensation arrangement by share-based payment award, equity instruments other than options, Grants in period			10,444