CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Sep. 30, 2015	Dec. 31, 2014
Statement Of Financial Position [Abstract]
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	75,000,000	75,000,000
Common stock, shares outstanding	47,725,176	46,858,415