Condensed Unaudited Consolidated Balance Sheets (Parenthetical) - $ / shares	Jun. 30, 2017	Dec. 31, 2016
Preferred stock, par value (in dollars per share)	$ 1	$ 1
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, shares authorized	145,000,000	145,000,000
Common stock, shares issued	90,825,531	90,634,771
Treasury stock, shares	8,094,004	8,094,004
Restricted Shares [Member] | Common Stock [Member]
Unvested restricted shares (in shares)	1,802,346	1,927,286