Share Based Compensation (Details Textual) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Share Based Compensation (Textual) [Abstract]
Share-based compensation expense	$ 3.2	$ 3.1
Tax benefits	$ 1.2	$ 1.1
Stock Option SAR Awards [Member]
Additional Share Based Compensation (Textual) [Abstract]
Stock awards	316,500
Restricted Stock and Performance Share Awards [Member]
Additional Share Based Compensation (Textual) [Abstract]
Stock awards	63,980
Phantom Stock Units [Member]
Additional Share Based Compensation (Textual) [Abstract]
Stock awards	68,780
Stock Options/SARs Granted Since 2004 [Member]
Additional Share Based Compensation (Textual) [Abstract]
Stock awards	5,253