Share Based Compensation (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Share Based Compensation (Textual) [Abstract]
Share-based compensation expense	$ 3.2	$ 3.0	$ 6.4	$ 6.1
Tax benefits	$ 1.2	$ 1.2	$ 2.4	$ 2.3
Stock Option SAR Awards [Member]
Additional Share Based Compensation (Textual) [Abstract]
Stock awards			317,100
Restricted Stock and Performance Share Awards [Member]
Additional Share Based Compensation (Textual) [Abstract]
Stock awards			64,220
Phantom Stock Units [Member]
Additional Share Based Compensation (Textual) [Abstract]
Stock awards			68,780
Stock Options SARs Granted Since Two Thousand Four [Member]
Additional Share Based Compensation (Textual) [Abstract]
Stock awards			10,166