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Consolidated Statements of Stockholders' Equity (unaudited) (Parenthetical) - $ / shares | 3 Months Ended
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Mar. 31, 2018 | Mar. 31, 2017
Consolidated Statements of Stockholders' Equity (unaudited) [Abstract] |  |
Cash dividends - per share (in dollars per share) | $ 0.48 | $ 0.23
Net issuance of shares to employee benefit plans and other stock plans (in shares) | 72,844 | 184,651

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- Definition Number of shares issued during the period to an employee benefit plans and other stock plans. + References No definition available. + Details
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- Definition The per share amount of a dividend declared, but not paid, as of the financial reporting date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586 + Details
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