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Share-Based Payments (Tables) | 12 Months Ended
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Dec. 31, 2017
Disclosure of Compensation Related Costs, Share-based Payments [Abstract] |
Summary of Restricted Share Units by Grant Year | The following table summarizes information about RSUs as at December 31, 2017 by year of grant:
|  |  | As at December 31, 2017
|  |  | Restricted Share Units
RSU Holder |  |  | Amount Granted |  | Amount Vested |  | Amount Forfeited |  | Amount Outstanding
2015 Grants |  | 287,852 |  |  | 173,755 |  |  | 38,886 |  |  | 75,211 |
2016 Grants |  | 328,550 |  |  | 104,042 |  |  | 40,579 |  |  | 183,929 |
2017 Grants |  | 200,021 |  |  | — |  |  | 19,585 |  |  | 180,436 |
Total |  |  |  |  |  |  |  | 439,576 |
Summary of Restricted Share Unit Activity under 2013 Share Incentive Plan | A summary of RSUs under the Company’s 2013 Share Incentive Plan for the twelve months ended December 31, 2017, 2016 and 2015 is presented below:
|  |  | Twelve Months Ended
|  |  | December 31, 2017 |  | December 31, 2016 |  | December 31, 2015
Restricted share unit activity |  |  | Number of Shares | Weighted Average Grant Date FV |  | Number of Shares | Weighted Average Grant Date FV |  | Number of Shares | Weighted Average Grant Date FV
Outstanding restricted stock, beginning of period |  | 530,340 |  | $39.28 |  | 504,234 |  | $40.45 |  | 519,112 |  | $35.82
Granted |  | 200,021 |  | 49.20 |  | 328,550 |  | 37.63 |  | 287,852 |  | 39.68
Vested |  | (245,704 | ) | 39.63 |  | (246,489 | ) | 34.26 |  | (266,944 | ) | 34.26
Forfeited |  | (45,081 | ) | 41.84 |  | (55,955 | ) | 39.51 |  | (35,786 | ) | 39.59
Outstanding restricted stock, end of period |  | 439,576 |  | $43.22 |  | 530,340 |  | $39.28 |  | 504,234 |  | $40.45
Summary of Performance and Phantom Shares by Grant Year | The following table summarizes information about phantom shares as at December 31, 2017 by year of grant:
|  | As at December 31, 2017
|  | Phantom Share Awards
|  | Amount Granted |  | Amount Vested |  | Amount Forfeited |  | Amount Outstanding
2015 Grants |  | 135,651 |  |  | 52,720 |  |  | 82,931 |  |  | — |
2016 Grants |  | 147,513 |  |  | 15,132 |  |  | 96,978 |  |  | 35,403 |
2017 Grants |  | 173,619 |  |  | — |  |  | 90,342 |  |  | 83,277 |
Total |  |  |  |  |  |  |  | 118,680 |
The following table summarizes information about performance shares as at December 31, 2017 by year of grant:
|  | As at December 31, 2017
|  | Performance Share Awards
|  | Amount Granted |  | Amount Vested |  | Amount Forfeited |  | Amount Outstanding
2015 Grants |  | 277,585 |  |  | 107,882 |  |  | 169,703 |  |  | — |
2016 Grants |  | 278,477 |  |  | 28,566 |  |  | 168,224 |  |  | 81,687 |
2017 Grants |  | 216,878 |  |  | — |  |  | 89,643 |  |  | 127,235 |
Total |  |  |  |  |  |  |  | 208,922 |
Summary of Performance and Phantom Share Activity under 2013 Share Incentive Plan | A summary of performance share activity under the Company’s 2013 Share Incentive Plan for the twelve months ended December 31, 2017, 2016 and 2015 is presented below:
|  |  | Twelve Months Ended
|  |  | December 31, 2017 |  | December 31, 2016 |  | December 31, 2015
Performance Share Activity |  |  | Number of Shares | Weighted Average Grant Date FV |  | Number of Shares | Weighted Average Grant Date FV |  | Number of Shares | Weighted Average Grant Date FV
Outstanding performance shares, beginning of period |  | 254,988 |  | $36.92 |  | 266,424 |  | $24.17 |  | 268,418 |  | $25.35
Granted |  | 216,878 |  | 47.30 |  | 278,477 |  | 34.44 |  | 277,585 |  | 38.92
Vested |  | — |  | — |  |  | (87,059 | ) | 37.30 |  | (208,830 | ) | 38.11
Forfeited |  | (262,944 | ) | 40.32 |  | (202,854 | ) | 36.93 |  | (70,749 | ) | 30.26
Outstanding performance shares, end of period |  | 208,922 |  | $38.71 |  | 254,988 |  | $36.92 |  | 266,424 |  | $24.17
A summary of phantom share activity under the Company’s 2013 Share Incentive Plan for the twelve months ended December 31, 2017, 2016 and 2015 is presented below:
|  |  | Twelve Months Ended
|  |  | December 31, 2017 |  | December 31, 2016 |  | December 31, 2015
Phantom Share Activity |  |  | Number of Shares | Weighted Average Grant Date FV |  | Number of Shares | Weighted Average Grant Date FV |  | Number of Shares | Weighted Average Grant Date FV
Outstanding performance shares, beginning of period |  | 131,464 |  | $35.90 |  | 130,319 |  | $38.75 |  | 143,248 |  | $35.32
Granted |  | 173,619 |  | 47.30 |  | 147,513 |  | 34.44 |  | 135,651 |  | 38.92
Vested |  | — |  | — |  |  | (36,159 | ) | 36.96 |  | (151,668 | ) | 34.98
Forfeited |  | (186,403 | ) | 40.32 |  | (110,209 | ) | 36.96 |  | 3,087 |  | 35.65
Outstanding performance shares, end of period |  | 118,680 |  | $38.71 |  | 131,464 |  | $35.90 |  | 130,319 |  | $38.75
Summary of Vesting Criteria | A summary of the increases in adjusted BVPS is presented below:
Year ended December 31, |  | Increase in BVPS
2013 |  | 6.2 | %
2014 |  | 13.3 | %
2015 |  | 10.7 | %
2016 |  | 5.9 | %
2017 |  | — | %
Fair Value of Employee Options Granted under ESPP | The fair value of the employee options granted under the ESPP was estimated on the date of grant using a modified Black-Scholes option pricing model under the following assumptions:
Grant Date |  | Per share weighted average fair value |  | Risk free interest rate |  | Dividend yield |  | Expected life |  | Share price volatility
|  | ($) |  | (%) |  | (%) |  | (in years) |  | (%)
March 25, 2015 |  | 8.17 |  | 0.94 |  |  | 1.78 |  |  | 3 |  | 16.00 |
March 25, 2015 |  | 7.08 |  | 0.60 |  |  | 1.78 |  |  | 2 |  | 16.00 |
March 25, 2016 |  | 7.97 |  | 1.04 |  |  | 1.88 |  |  | 3 |  | 4.21 |
March 25, 2016 |  | 7.00 |  | 0.87 |  |  | 1.88 |  |  | 2 |  | 2.44 |
April 28, 2017 |  | 6.69 |  | 1.44 |  |  | 1.83 |  |  | 3 |  | 3.67 |
April 28, 2017 |  | 8.70 |  | 1.44 |  |  | 1.83 |  |  | 3 |  | 3.67 |
April 28, 2017 |  | 8.70 |  | 1.26 |  |  | 1.83 |  |  | 2 |  | 3.52 |
Summary of Non-Employee Director Restricted Share Units by Grant Year | The following table summarizes information about RSUs issued to non-employee directors by year of grant as at December 31, 2017.
|  | As at December 31, 2017
|  | Restricted Share Units
|  | Amount Granted |  | Amount Vested |  | Amount Forfeited |  | Amount Outstanding
Non-Employee Directors |  |  |  |  |  |  |  |
2015 |  | 27,620 |  |  | 27,620 |  |  | — |  |  | — |
2016 |  | 24,456 |  |  | 21,352 |  |  | 3,104 |  |  | — |
2017 |  | 22,230 |  |  | 17,043 |  |  | 1,853 |  |  | 3,334 |
Chairman |  |  |  |  |  |  |  |
2015 |  | 12,154 |  |  | 12,154 |  |  | — |  |  | — |
2016 |  | 10,952 |  |  | 10,952 |  |  | — |  |  | — |
2017 |  | 8,892 |  |  | 7,410 |  |  | — |  |  | 1,482 |
Total |  | 106,304 |  |  | 96,531 |  |  | 4,957 |  |  | 4,816 |
Summary of Restricted Share Unit, Non Employee Directors, under 2013 Share Incentive Plan | A summary of RSU activity relating to non-employee directors under the Company’s 2013 Share Incentive Plan for the twelve months ended December 31, 2017, 2016 and 2015 is presented below:
|  |  | Twelve Months Ended
|  |  | December 31, 2017 |  | December 31, 2016 |  | December 31, 2015
Restricted share unit activity |  |  | Number of Shares | Weighted Average Grant Date FV |  | Number of Shares | Weighted Average Grant Date FV |  | Number of Shares | Weighted Average Grant Date FV
Outstanding restricted stock, beginning of period |  | 5,171 |  | $41.07 |  | 6,636 |  | $45.28 |  | 6,806 |  | $35.83
Granted |  | 31,122 |  | 50.18 |  | 35,408 |  | 41.07 |  | 39,774 |  | 45.25
Vested |  | (29,624 | ) | 48.59 |  | (33,769 | ) | 41.89 |  | (39,944 | ) | 43.81
Forfeited |  | (1,853 | ) | 50.18 |  | (3,104 | ) | 41.07 |  | — |  | 0.00
Outstanding restricted stock, end of period |  | 4,816 |  | $50.19 |  | 5,171 |  | $41.07 |  | 6,636 |  | $45.28

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