Common Stock Activity (Summary of Share Activity) (Details)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Rollforward of Share Activity, Common and Treasury Shares
Shares issued for stock option exercises	194,200	20,000
Treasury shares, beginning balance	9,467,286
Treasury shares, ending balance	9,467,286
Common Stock Outstanding Member [Member]
Rollforward of Share Activity, Common and Treasury Shares
Common shares outstanding, beginning balance	76,448,000
Shares issued for stock option exercises	194,000
Shares issued for restricted stock awards	21,000
Other shares issued	125,000
Common shares outstanding, ending balance	76,789,000