Shareholders' Equity (Details Textual) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 25, 2019
Shareholders' Equity (Textual)
Common stock authorized under repurchase program				$ 300,000,000
Stock repurchases, Shares	0	2,000,000.0	1,500,000
Payments for stock repurchases	$ 0	$ (150,000,000.0)	$ (115,500,000)
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	67,751,074	67,536,794
Common stock, shares outstanding	35,047,317	34,833,037
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