Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - $ / shares	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Additional Paid-in Capital [Member]
Award of common shares released from Employee Benefit Trust (in shares)	134,005	139,607
Shares issued upon vesting of restricted stock unit awards (in shares)	245,111	204,110
Issuance upon exercise of stock options (in shares)	27,945	9,725
Treasury Stock [Member] | Shares Purchased to Fund Options Exercised [Member]
Purchases of shares (in shares)	378,695	635,199
Treasury Stock [Member] | Restricted Stock Awards Repurchased to Satisfy Tax Obligations [Member]
Purchases of shares (in shares)	77,212	58,461
Retained Earnings [Member]
Cash dividends declared and paid on common shares (in dollars per share)	$ 0.34	$ 0.32
Issuance upon exercise of stock options (in shares)	27,945