Consolidated Statements of Changes in Stockholders Equity (Unaudited) (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Common stock
Common stock transactions:
Common shares purchased and retired	998,135	789,743
Common shares issued	16,085	21,414
Non-vested common shares issued	189,624	169,577
Non-vested common shares forfeited	25,984	3,484
Stock options exercised	270,183	217,824
Shares tendered in payment of option price and income tax withholding amounts	94,902	58,996
Retained earnings
Cash dividends declared:
Common (in dollars per share)	$ 0.66	$ 0.60