Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (Parentheticals) - USD ($) $ in Thousands	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015
Retained Earnings [Member]
Dividends, per share (in dollars per share)	$ 0.55	$ 0.53
AOCI Attributable to Parent [Member]
Other comprehensive income (loss), tax	$ 2,153	$ (1,729)
Dividends, per share (in dollars per share)	$ 0.55	$ 0.53
Other comprehensive income (loss), tax	$ 2,153	$ (1,729)

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

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 220
-SubTopic 10
-Section 45
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=66004124&loc=d3e640-108580

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 20
-Section 45
-Paragraph 11
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65896914&loc=d3e39076-109324

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration