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Common Stock (Details) - $ / shares |  |  |  |  | 3 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | ---
Jan. 29, 2016 | Jan. 04, 2016 | Sep. 25, 2014 | Sep. 24, 2014 | Dec. 31, 2015 | Sep. 30, 2015 | Jun. 30, 2015 | Mar. 31, 2015 | Dec. 31, 2014 | Sep. 30, 2014 | Jun. 30, 2014 | Mar. 31, 2014 | Dec. 31, 2015 | Dec. 31, 2014 | Dec. 31, 2013 | Aug. 06, 2015
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Authorized shares to be repurchased |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 1,000,000
Dividends declared (in dollars per share) |  |  |  |  | $ 0.08 | $ 0.08 | $ 0.08 | $ 0.08 | $ 0.07 | $ 0.07 | $ 0.07 | $ 0.07 |  |  |  |
Dividends paid (in dollars per share) |  |  |  |  |  |  |  |  |  |  |  |  | $ 0.32 | $ 0.28 | $ 0.28 |
Subsequent Event |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividends declared (in dollars per share) |  | $ 0.09 |  |  |  |  |  |  |  |  |  |  |  |  |  |
Dividends paid (in dollars per share) | $ 0.09 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Share Repurchase Agreement with Capital Southwest Corporation and Capital Southwest Venture Corporation |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Class of Stock [Line Items] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Authorized shares to be repurchased |  |  |  | 849,690 |  |  |  |  |  |  |  |  |  |  |  |
Purchase price per share |  |  |  | $ 40.255 |  |  |  |  |  |  |  |  |  |  |  |
Share Price (in dollars per share) |  |  |  | $ 41.50 |  |  |  |  |  |  |  |  |  |  |  |
Retirement of shares (shares) |  |  | 849,690 |  |  |  |  |  |  |  |  |  |  |  |  |

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- Definition Aggregate dividends paid during the period for each share of common stock outstanding. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.3-04) -URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770 + Details
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