CONDENSED CONSOLIDATED STATEMENTS OF CONDITION - (Parenthetical) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Common stock, par value	$ 1	$ 1
Common stock, shares authorized	100,000,000	100,000,000
Common stock, shares issued	35,511,943	23,996,293
Common stock, shares outstanding	35,511,943	23,996,293