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Equity-Based Compensation (Summary of Ranges of Outstanding and Exercisable Options) (Details) - $ / shares | 12 Months Ended |
--- | --- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |  |
Options Outstanding | 247,666 | 277,224 | 458,349 | 569,319
Weighted Average Remaining Contractual Life (in years) | 5 years 3 months 7 days |  |  |
Weighted Average Exercise Price | $ 16.02 | $ 19.08 | $ 15.13 |
Options Exercisable | 197,666 |  |  |
$8.90 – $9.32 |  |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |  |
Exercise Price Range, Lower Range Limit | $ 8.90 |  |  |
Exercise Price Range, Upper Range Limit | $ 9.32 |  |  |
Options Outstanding | 28,750 |  |  |
Weighted Average Remaining Contractual Life (in years) | 2 years 8 months 12 days |  |  |
Weighted Average Exercise Price | $ 8.90 |  |  |
Options Exercisable | 28,750 |  |  |
Weighted Average Exercise Price | $ 8.90 |  |  |
$9.33 – $11.73 |  |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |  |
Exercise Price Range, Lower Range Limit | 9.33 |  |  |
Exercise Price Range, Upper Range Limit | $ 11.73 |  |  |
Options Outstanding | 92,441 |  |  |
Weighted Average Remaining Contractual Life (in years) | 3 years 8 months 12 days |  |  |
Weighted Average Exercise Price | $ 9.74 |  |  |
Options Exercisable | 92,441 |  |  |
Weighted Average Exercise Price | $ 9.74 |  |  |
$11.74 – $17.94 |  |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |  |
Exercise Price Range, Lower Range Limit | 11.74 |  |  |
Exercise Price Range, Upper Range Limit | $ 17.94 |  |  |
Options Outstanding | 39,475 |  |  |
Weighted Average Remaining Contractual Life (in years) | 1 year 8 months 12 days |  |  |
Weighted Average Exercise Price | $ 13.72 |  |  |
Options Exercisable | 39,475 |  |  |
Weighted Average Exercise Price | $ 13.72 |  |  |
$17.95 – $23.80 |  |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |  |
Exercise Price Range, Lower Range Limit | 17.95 |  |  |
Exercise Price Range, Upper Range Limit | $ 23.80 |  |  |
Options Outstanding | 37,000 |  |  |
Weighted Average Remaining Contractual Life (in years) | 8 months 9 days |  |  |
Weighted Average Exercise Price | $ 22.16 |  |  |
Options Exercisable | 37,000 |  |  |
Weighted Average Exercise Price | $ 22.16 |  |  |
$23.81 – $43.05 |  |  |  |
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items] |  |  |  |
Exercise Price Range, Lower Range Limit | 23.81 |  |  |
Exercise Price Range, Upper Range Limit | $ 43.05 |  |  |
Options Outstanding | 50,000 |  |  |
Weighted Average Remaining Contractual Life (in years) | 8 years 6 months 26 days |  |  |
Weighted Average Exercise Price | $ 33.90 |  |  |
Options Exercisable | 0 |  |  |
Weighted Average Exercise Price | $ 0 |  |  |

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- Definition The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iii) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(iii) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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- Definition Number of options outstanding, including both vested and non-vested options. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
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