Shareholders' Equity (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Mar. 31, 2014
Shareholders' Equity (Textual)
Common stock authorized under repurchase program		$ 200,000,000		$ 250,000,000
Stock repurchases, Shares	(1,900,000)	(1,400,000)	0
Payments for stock repurchases	$ (124,600,000)	$ (68,600,000)	$ 0
Common stock, shares authorized	120,000,000	120,000,000
Common Stock, Par or Stated Value Per Share	$ 0.625	$ 0.625
Common stock, shares issued	66,600,984	66,349,906
Common stock, shares outstanding	44,198,850	45,868,698
Series A and B $2.50 Cumulative Convertible Preferred Stock [Member]
Shareholders' Equity (Textual)
Preferred stock, shares authorized	5,000,000
Preferred stock, par value	$ 1.00
Preferred stock, shares outstanding		15,567
Cumulative annual cash dividend per share on preferred stock	$ 2.50