Consolidated Statements of Changes in Stockholders' Equity (Parentheticals)	12 Months Ended
Dec. 31, 2016 $ / shares	Dec. 31, 2015 $ / shares	Dec. 31, 2014 $ / shares
Retained Earnings [Member]
Cash dividends (in dollars per share)	$ 0.72	$ 0.64	$ 0.59
Common Stock [Member] \| Stock Split To [Member]
Stock split	3
Common Stock [Member] \| Stock Split From [Member]
Stock split	2

Ratio applied to the conversion of stock split, for example but not limited to, one share converted to two or two shares converted to one.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SAB TOPIC 4.C)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187143-122770

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Stock Split
-URI http://asc.fasb.org/extlink&oid=6525746

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