CONSOLIDATED BALANCE SHEETS (Unaudited) (Parenthetical) - $ / shares	Mar. 31, 2017	Dec. 31, 2016
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	15,283,624	13,937,627