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Stock-based compensation (Tables) | 12 Months Ended
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Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Schedule of stock-based compensation expenses included in general and administrative expenses | Stock-based compensation expenses included in general and administrative expenses are as follows:
Year ended December 31, |  | 2015 |  |  | 2014 |  |  | 2013 |
Share option plan (note 22(b)) |  | $ | 716 |  |  | $ | 921 |  |  | $ | 981 |
Liability classified restricted share unit plan (note 22(d(i))) |  | (80 | ) |  | 790 |  |  | 2,652 |
Equity classified restricted share unit plan (note 22(d(ii))) |  | 713 |  |  | 419 |  |  | — |
Equity performance restricted share unit plan (note 22(e)) |  | 431 |  |  | 94 |  |  | — |
Liability classified deferred stock unit plan (note 22(f(i))) |  | (735 | ) |  | (1,100 | ) |  | 2,560 |
Equity classified deferred stock unit plan (note 22(f(ii))) |  | 651 |  |  | 2,181 |  |  | — |
|  | $ | 1,696 |  |  | $ | 3,305 |  |  | $ | 6,193 |
Schedule of stock options activity |
|  | Number of options |  |  | Weighted average exercise price $ per share |
Outstanding at December 31, 2012 |  | 3,029,734 |  |  | 5.70 |
Granted |  | 177,400 |  |  | 5.91 |
Exercised(i) |  | (295,230 | ) |  | 3.98 |
Forfeited |  | (698,624 | ) |  | 7.12 |
Outstanding at December 31, 2013 |  | 2,213,280 |  |  | 5.51 |
Exercised(i) |  | (385,880 | ) |  | 3.49 |
Forfeited |  | (61,480 | ) |  | 7.83 |
Outstanding at December 31, 2014 |  | 1,765,920 |  |  | 5.87 |
Exercised(i) |  | (30,080 | ) |  | 2.75 |
Forfeited |  | (287,840 | ) |  | 8.91 |
Outstanding at December 31, 2015 |  | 1,448,000 |  |  | 5.33 |
(i) | All stock options exercised resulted in new common shares being issued (note 17(a)).
Summary of information about stock options outstanding | The following table summarizes information about stock options outstanding at December 31, 2015:
|  | Options outstanding |  |  | Options exercisable |
Exercise price |  | Number |  |  | Weighted average remaining life |  | Weighted average exercise price |  |  | Number |  |  | Weighted average remaining life |  | Weighted average exercise price |
$2.75 |  | 288,900 |  |  | 6.4 years |  | $ | 2.75 |  |  | 149,420 |  |  | 6.5 years |  | $ | 2.75 |
$2.79 |  | 450,000 |  |  | 6.5 years |  | $ | 2.79 |  |  | 150,000 |  |  | 6.5 years |  | $ | 2.79 |
$3.69 |  | 29,100 |  |  | 2.9 years |  | $ | 3.69 |  |  | 29,100 |  |  | 2.9 years |  | $ | 3.69 |
$4.90 |  | 40,000 |  |  | 6.3 years |  | $ | 4.90 |  |  | 24,000 |  |  | 6.3 years |  | $ | 4.90 |
$5.00 |  | 127,760 |  |  | 0.4 years |  | $ | 5.00 |  |  | 127,760 |  |  | 0.4 years |  | $ | 5.00 |
$5.91 |  | 149,200 |  |  | 8.0 years |  | $ | 5.91 |  |  | 59,680 |  |  | 8.0 years |  | $ | 5.91 |
$6.56 |  | 79,860 |  |  | 5.9 years |  | $ | 6.56 |  |  | 63,080 |  |  | 5.9 years |  | $ | 6.56 |
$8.28 |  | 10,000 |  |  | 3.5 years |  | $ | 8.28 |  |  | 10,000 |  |  | 3.5 years |  | $ | 8.28 |
$8.58 |  | 30,000 |  |  | 4.7 years |  | $ | 8.58 |  |  | 30,000 |  |  | 4.7 years |  | $ | 8.58 |
$9.33 |  | 59,780 |  |  | 4.1 years |  | $ | 9.33 |  |  | 59,780 |  |  | 4.1 years |  | $ | 9.33 |
$10.13 |  | 59,060 |  |  | 5.0 years |  | $ | 10.13 |  |  | 59,060 |  |  | 5.0 years |  | $ | 10.13 |
$13.50 |  | 74,340 |  |  | 1.9 years |  | $ | 13.50 |  |  | 74,340 |  |  | 1.9 years |  | $ | 13.50 |
$16.46 |  | 50,000 |  |  | 2.3 years |  | $ | 16.46 |  |  | 50,000 |  |  | 2.3 years |  | $ | 16.46 |
|  | 1,448,000 |  |  | 5.4 years |  | $ | 5.33 |  |  | 886,220 |  |  | 4.6 years |  | $ | 6.52 |
Schedule of performance restricted share units |
|  | Number of units
Outstanding at December 31, 2013 |  | — |
Granted |  | 65,636 |
Dividend equivalents granted |  | 536 |
Outstanding at December 31, 2014 |  | 66,172 |
Granted |  | 350,724 |
Dividend equivalents granted |  | 6,696 |
Outstanding at December 31, 2015 |  | 423,592 |
Schedule of stock plan activity | Liability classified deferred stock unit plan
|  | Number of units |
Outstanding at December 31, 2012 |  | 625,156 |
Issued |  | 141,509 |
Redeemed |  | (179,831 | )
Outstanding at December 31, 2013 |  | 586,834 |
Issued |  | 7,674 |
Redeemed |  | (63,886 | )
Outstanding at December 31, 2014 |  | 530,622 |
Issued |  | — |
Modified |  | 571,569 |
Redeemed |  | (173,317 | )
Outstanding at December 31, 2015 |  | 928,874 |
Senior executive stock option plan |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Schedule of assumptions used to value stock option grants | The weighted average assumptions used in estimating the fair value of the fully vested senior executive stock options as at December 31, 2015 and 2014 are as follows:
Year ended December 31, |  | 2015 |  |  | 2014 |  |  | 2013 |
Number of senior executive stock options |  | — |  |  | 258,200 |  |  | 550,000 |
Weighted average fair value per option granted ($) |  | — |  |  | 0.08 |  |  | 1.71 |
Weighted average assumptions: |  |  |  |  |  |
Dividend yield |  | — | % |  | 2.20 | % |  | N/A |
Expected volatility |  | — | % |  | 49.68 | % |  | 39.12 | %
Risk-free interest rate |  | — | % |  | 0.25 | % |  | 0.22 | %
Expected life (years) |  | 0.0 |  |  | 0.4 |  |  | 1.4 |
Liability classified restricted share unit plan |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Schedule of restricted share unit plan activity | Liability classified restricted share unit plan
|  | Number of units |
Outstanding at December 31, 2012 |  | 1,110,275 |
Granted |  | 555,204 |
Vested |  | (154,330 | )
Forfeited |  | (487,205 | )
Outstanding at December 31, 2013 |  | 1,023,944 |
Dividend equivalents granted |  | 695 |
Vested |  | (350,271 | )
Forfeited |  | (58,865 | )
Outstanding at December 31, 2014 |  | 615,503 |
Dividend equivalents granted |  | — |
Vested |  | (277,707 | )
Forfeited |  | (47,006 | )
Outstanding at December 31, 2015 |  | 290,790 |
Equity classified restricted share unit plan |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Schedule of restricted share unit plan activity | Equity classified restricted share unit plan
|  | Number of units |  |  | Weighted average exercise price $ per share |
Outstanding at December 31, 2013 |  | — |  |  | — |
Granted |  | 274,256 |  |  | 7.98 |
Dividend equivalents granted |  | 11,557 |  |  | 6.15 |
Vested |  | (605 | ) |  | 7.75 |
Forfeited |  | (22,300 | ) |  | 7.87 |
Outstanding at December 31, 2014 |  | 262,908 |  |  | 7.91 |
Granted |  | 557,650 |  |  | 3.01 |
Dividend equivalents granted |  | 22,882 |  |  | 3.03 |
Modified |  | (156 | ) |  | 3.62 |
Vested |  | (19,798 | ) |  | 3.63 |
Forfeited |  | (49,330 | ) |  | 6.37 |
Outstanding at December 31, 2015 |  | 774,156 |  |  | 4.45 |
Deferred share unit plan |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Schedule of stock plan activity | Equity classified deferred stock unit plan
|  | Number of units |  |  | Weighted average exercise price $ per share |
Outstanding at December 31, 2013 |  | — |  |  | — |
Granted |  | 161,007 |  |  | 6.52 |
Dividend equivalents issued |  | 8,721 |  |  | 6.10 |
Outstanding at December 31, 2014 |  | 169,728 |  |  | 6.50 |
Issued |  | 378,867 |  |  | 3.29 |
Dividend equivalents granted |  | 22,974 |  |  | 3.07 |
Modified |  | (571,569 | ) |  | 2.58 |
Outstanding at December 31, 2015 |  | — |  |  | — |

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- Definition Tabular disclosure of share-based compensation plans that may be presented in a single table for outstanding, vested and expected to vest, and exercisable awards. The information that may be disclosed in this table may include, but is not limited to, number of shares, weighted average exercise price, weighted average remaining contractual life, and aggregate intrinsic value. + References No definition available. + Details
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- Definition Tabular disclosure of the number and weighted-average grant date fair value for restricted stock units that were outstanding at the beginning and end of the year, and the number of restricted stock units that were granted, vested, or forfeited during the year. + 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) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Tabular disclosure of the number and weighted-average exercise prices (or conversion ratios) for share options (or share units) that were outstanding at the beginning and end of the year, vested and expected to vest, exercisable or convertible at the end of the year, and the number of share options or share units that were granted, exercised or converted, forfeited, and expired during the year. + 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) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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- Definition Tabular disclosure of the significant assumptions used during the year to estimate the fair value of stock options, including, but not limited to: (a) expected term of share options and similar instruments, (b) expected volatility of the entity's shares, (c) expected dividends, (d) risk-free rate(s), and (e) discount for post-vesting restrictions. + 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) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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