Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Statement of Financial Position [Abstract]
Preferred stock, par value (in dollars per share)	$ 1	$ 1	$ 1	$ 1	$ 1
Preferred stock, shares authorized	5,000,000	5,000,000	5,000,000	5,000,000	5,000,000
Preferred stock, shares issued	0	0	0	0	0
Preferred stock, shares outstanding	0	0	0	0	0
Common stock, par value (in dollars per share)	$ 0.10	$ 0.1	$ 0.1	$ 0.1	$ 0.10
Common stock, shares authorized	145,000,000	145,000,000	145,000,000	145,000,000	145,000,000
Common stock, shares issued	87,614,955	87,106,042	87,036,192	86,993,988	86,725,372
Treasury stock, shares	2,876,311	5,262,831	5,262,831	9,467,286	9,467,286