Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (Parenthetical) - $ / shares	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Consolidated Statements of Changes in Shareholders' Equity (Unaudited) [Abstract]
Cash dividend declared (in dollars per share)	$ 0.1312	$ 0.1312
Stock options exercised (in shares)	296,300	97,600
Purchase of treasury stock (in shares)	213,356	80,769
Sale of treasury stock (in shares)	151,762	213,748