Consolidated Statements of Changes in Stockholders Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Common stock
Common stock transactions:
Common shares purchased and retired	967,965	588,409
Common shares issued	0	0
Non-vested common shares issued	182,544	156,956
Non-vested common shares forfeited	12,347	838
Stock options exercised	77,028	73,344
Shares tendered in payment of option price and income tax withholding amounts	34,816	22,042
Retained earnings
Cash dividends declared:
Common (in dollars per share)	$ 0.22	$ 0.20