Shareholders' Equity (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jan. 31, 2016	Jan. 31, 2014
Shareholders' Equity (Textual)
Common stock authorized under repurchase program				$ 300,000,000	$ 250,000,000
Stock repurchases, Shares	2,700,000	2,400,000	1,900,000
Payments for stock repurchases	$ (120,100,000)	$ (125,400,000)	$ (124,600,000)
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	66,953,606	66,776,290
Common stock, shares outstanding	39,442,893.000000	41,970,098
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