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Share-based compensation (Details) $ in Thousands | 12 Months Ended |
--- | --- | ---
Dec. 31, 2016 USD ($) award_type shares | Dec. 31, 2015 USD ($) shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Options to purchase common stock (shares) |  | 443,737
Service-Based Share Awards [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Service-based share awards outstanding (shares) | 741,036 | 541,304
Amended and Restated Stock Option Plan [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Shares authorized (shares) | 10,000,000 |
Shares remaining (shares) | 6,595,000 |
Share based compensation, vesting rights (in time period) | 3 years |
Expected term (years) | 10 years |
Options to purchase common stock (shares) | 359,570 |
Amended and Restated Stock Option Plan [Member] | Non-employee director [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Share based compensation, vesting rights (in time period) | 12 months |
Amended and Restated Stock Option Plan [Member] | Service-Based Share Awards [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Service-based share awards outstanding (shares) | 741,036 |
Amended and Restated Stock Option Plan [Member] | Initial vesting -grant date [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Award vesting rights | 33.33% |
Amended and Restated Stock Option Plan [Member] | Year one [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Award vesting rights | 33.33% |
Amended and Restated Stock Option Plan [Member] | Year two [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Award vesting rights | 33.33% |
Long Term Incentive Plan [Member] |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |
Share based compensation, vesting rights (in time period) | 3 years |
Number of award types provided | award_type | 2 |
Performance unit liability | $ | $ 5,511 | $ 4,853

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- Definition Aggregate carrying value as of the balance sheet date of the liabilities for all deferred compensation arrangements. Represents currently earned compensation under compensation arrangements that is not actually paid until a later date. + References No definition available. + Details
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- Definition Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + 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 (a)(1) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date. + 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)(2)(i)-(ii) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + 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 (a)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable. + 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=6415400&loc=d3e5070-113901 + Details
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- Definition Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + 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 (f)(2)(i) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.D.2) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 + Details
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