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Common Stock and Dividends (Details) - USD ($) |  |  |  |  |  |  | 1 Months Ended | 3 Months Ended | 6 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Nov. 05, 2018 | Oct. 16, 2018 | Apr. 16, 2018 | Oct. 16, 2017 | Apr. 17, 2017 | Apr. 09, 2017 | Apr. 30, 2009 | Sep. 30, 2018 | Jun. 30, 2018 | Sep. 30, 2018 | Dec. 31, 2008 | Apr. 03, 2018
Common Stock and Dividends |  |  |  |  |  |  |  |  |  |  |  |
Warrants to purchase entity's common stock (in shares) |  |  |  |  |  |  |  |  |  |  | 1,326,238 |
Warrants, exercise price (in dollars per share) |  |  |  |  |  |  |  |  |  |  | $ 24.43 |
Warrants, term |  |  |  |  |  |  |  |  |  |  | 10 years |
Payments for Repurchase of Warrants |  |  |  |  |  |  |  | $ 29,005,000 |  | $ 29,005,000 |  |
Maximum cash dividend paid in semi-annual period (in dollars per share) |  |  |  |  |  |  |  |  | $ 0.33 |  |  |
Cash dividends paid to common shareholders (in dollars per share) |  | $ 0.42 | $ 0.33 | $ 0.33 | $ 0.33 |  |  |  |  |  |  |
Repurchase of common stock, authorized amount |  |  |  |  |  |  | $ 40,000,000 |  |  |  |  | $ 40,000,000
Period of repurchase of common stock |  |  |  |  |  | 12 months | 12 months |  |  |  |  |
Cumulative number of shares repurchased under all stock repurchase programs | 9,246,956 |  |  |  |  |  |  |  |  |  |  |
Cumulative cost of shares repurchased under all stock repurchase programs | $ 271,347,000 |  |  |  |  |  |  |  |  |  |  |

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- Definition Represents the maximum amount of cash dividends paid per semi-annual period before adjustments will be made to the exercise price of the warrant. + References No definition available. + Details
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- Definition The cumulative number of shares that have been repurchased under all stock repurchase programs as of a certain date. + References No definition available. + Details
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- Definition Exercise price per share or per unit of warrants or rights outstanding. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(4)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
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- Definition Number of securities into which the class of warrant or right may be converted. For example, but not limited to, 500,000 warrants may be converted into 1,000,000 shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(i)(2)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
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- Definition The aggregate amount paid by the entity to reacquire the right to purchase equity shares at a predetermined price, usually issued together with corporate debt. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 15 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3291-108585 + Details
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- Definition Period which shares may be purchased under a stock repurchase plan authorized by an entity's Board of Directors, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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