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v3.10.0.1

Impact of change in accounting policies Statement of shareholders' equity (Details) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2018 | Jun. 30, 2017 | Jun. 30, 2018 | Jun. 30, 2017 | Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Ordinary shares, shares issued (in shares) | 54,327,869 |  | 54,327,869 |  | 54,081,601
Beginning balance |  |  | $ 1,191,000 |  |
Net income | $ 71,868 | $ 64,817 | 149,966 | $ 136,226 |
Currency translation adjustment |  |  | (20,813) |  |
Currency impact of long term funding |  |  | (3,055) |  |
Tax on currency impact of long term funding |  |  | 0 |  |
Unrealized capital gain – investments |  |  | (423) |  |
Amortization of interest rate hedge |  |  | (463) |  |
Fair value of cash flow hedge |  |  | (2,055) |  |
Total comprehensive income |  |  | 123,157 |  |
Exercise of share options |  |  | 10,301 |  |
Issue of restricted share units |  |  | 36 |  |
Non-cash stock compensation expense |  |  | 16,583 |  |
Share issuance costs |  |  | (9) |  |
Share repurchase program |  |  | 54,172 |  |
Share repurchase costs |  |  | 44 |  |
Ending balance | 1,238,748 |  | 1,238,748 |  |
Common Stock [Member] |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Ordinary shares, shares issued (in shares) |  |  |  |  | 54,081,601
Beginning balance |  |  | $ 4,664 |  |
Exercise of share options (in shares) |  |  | 226,888 |  |
Exercise of share options |  |  | $ 17 |  |
Issue of restricted share units (in shares) |  |  | 483,435 |  |
Issue of restricted share units |  |  | $ 36 |  |
Share repurchase program (in shares) |  |  | (464,055) |  |
Share repurchase program |  |  | $ 33 |  |
Additional Paid-in Capital |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Beginning balance |  |  | 481,337 |  |
Exercise of share options |  |  | 10,284 |  |
Non-cash stock compensation expense |  |  | 16,583 |  |
Share issuance costs |  |  | (9) |  |
Other Undenominated Capital |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Beginning balance |  |  | 912 |  |
Share repurchase program |  |  | (33) |  |
AOCI Attributable to Parent [Member] |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Beginning balance |  |  | (38,713) |  |
Currency translation adjustment |  |  | (20,813) |  |
Currency impact of long term funding |  |  | (3,055) |  |
Tax on currency impact of long term funding |  |  | 0 |  |
Unrealized capital gain – investments |  |  | (423) |  |
Amortization of interest rate hedge |  |  | (463) |  |
Fair value of cash flow hedge |  |  | (2,055) |  |
Retained Earnings [Member] |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Beginning balance |  |  | 742,800 |  |
Net income |  |  | 149,966 |  |
Currency translation adjustment |  |  |  |  |
Total comprehensive income |  |  | 149,966 |  |
Share repurchase program |  |  | 54,172 |  |
Share repurchase costs |  |  | 44 |  |
Ending balance | 790,446 |  | 790,446 |  |
Difference between Revenue Guidance in Effect before and after Topic 606 |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Net income |  |  | 2,334 |  |
Difference between Revenue Guidance in Effect before and after Topic 606 | Retained Earnings [Member] |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Net income |  |  | 2,334 |  |
Calculated under Revenue Guidance in Effect before Topic 606 |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Total comprehensive income |  |  | 125,491 |  |
Ending balance | $ 1,289,186 |  | $ 1,289,186 |  |
Calculated under Revenue Guidance in Effect before Topic 606 | Common Stock [Member] |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Ordinary shares, shares issued (in shares) | 54,327,869 |  | 54,327,869 |  |
Ending balance | $ 4,684 |  | $ 4,684 |  |
Calculated under Revenue Guidance in Effect before Topic 606 | Additional Paid-in Capital |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Ending balance | 508,195 |  | 508,195 |  |
Calculated under Revenue Guidance in Effect before Topic 606 | Other Undenominated Capital |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Ending balance | 945 |  | 945 |  |
Calculated under Revenue Guidance in Effect before Topic 606 | AOCI Attributable to Parent [Member] |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Total comprehensive income |  |  | (26,809) |  |
Ending balance | (65,522) |  | (65,522) |  |
Calculated under Revenue Guidance in Effect before Topic 606 | Retained Earnings [Member] |  |  |  |  |
Revenue, Initial Application Period Cumulative Effect Transition [Line Items] |  |  |  |  |
Total comprehensive income |  |  | 152,300 |  |
Ending balance | $ 840,884 |  | $ 840,884 |  |

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- Definition Number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP), net of any shares forfeited. Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(29)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(28)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=84159872&loc=d3e21463-112644 Reference 4: 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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