Consolidated Statements of Changes in Stockholders' Equity (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Consolidated Statements of Changes in Stockholders' Equity [Abstract]
Restricted stock compensation expense, shares	896
Exercise of stock options, shares	966	6,623
Cash dividends- common stock per share	$ 0.07	$ 0.07
Sale of treasury shares to 401(k), shares	3,230	2,960
Sale of treasury shares to deferred compensation plan, shares	1,480	1,303