Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - USD ($)	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017
Retained Earnings [Member]
Dividends, per share (in dollars per share)	$ 0.58	$ 0.56
AOCI Attributable to Parent [Member]
Other comprehensive income (loss), tax	$ (624)	$ 1,454
Dividends, per share (in dollars per share)	$ 0.58	$ 0.56

Amount of tax expense (benefit) allocated to other comprehensive income (loss).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 45
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-Name Accounting Standards Codification
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