Capital Stock and Stock Compensation (Narrative) (Details) - USD ($) |
1 Months Ended | 3 Months Ended | 9 Months Ended | ||||
---|---|---|---|---|---|---|---|
Feb. 14, 2017 |
Apr. 30, 2018 |
Sep. 30, 2018 |
Sep. 30, 2017 |
Sep. 30, 2018 |
Sep. 30, 2017 |
May 02, 2017 |
|
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||
Stock repurchase program, authorized amount | $ 30,000,000 | ||||||
Purchases Of Treasury Stock | $ 0 | $ 3,177,000 | |||||
Non-cash expense relating to stock compensation benefits | $ 2,203,000 | $ 2,733,000 | |||||
Restricted Stock [Member] | Directors [Member] | |||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||
Granted | 46,431 | ||||||
Weighted average grant date fair value per share | $ 18.74 | ||||||
Time Based Restricted Stock [Member] | Senior Officers [Member] | |||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||
Granted | 55,536 | ||||||
Weighted average grant date fair value per share | $ 17.46 | ||||||
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights | Each RSU represents a contingent right to receive one share of INSW common stock upon vesting. Each award of RSUs will vest in equal installments on each of the first three anniversaries of the grant date. | ||||||
Performance Shares [Member] | |||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||
Non-cash expense relating to stock compensation benefits | $ 0 | ||||||
Performance Shares [Member] | Senior Officers [Member] | |||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||
Granted | 55,534 | ||||||
Weighted average grant date fair value per share | $ 17.46 | ||||||
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights | Each performance stock unit represents a contingent right to receive RSUs based upon the covered employees being continuously employed through the end of the period over which the performance goals are measured and shall vest as follows: (i) one-half of the target RSUs shall vest on December 31, 2020, subject to INSW's return on invested capital ("ROIC") performance in the three-year ROIC performance period relative to a target rate (the "ROIC Target") set forth in the award agreements; and (ii) one-half of the target RSUs shall vest on December 31, 2020, subject to INSW's three-year total shareholder return ("TSR") performance relative to that of a performance peer group over a three-year performance period ("TSR Target"). Vesting is subject in each case to the Human Resources and Compensation Committee of the Company's Board of Directors' certification of achievement of the performance measures and targets no later than March 15, 2021. As of September 30, 2018, INSW management believes the ROIC Target performance condition is not probable of being achieved. | ||||||
Non-cash expense relating to stock compensation benefits | $ 0 | ||||||
Performance Shares [Member] | Executive Officer [Member] | |||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||
Weighted average grant date fair value per share | $ 17.46 | ||||||
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights | Each performance stock unit represents a contingent right to receive RSUs based upon certain performance related goals being met and the covered employees being continuously employed through the end of the period over which the performance goals are measured. These performance awards shall vest on December 31, 2018, subject to INSW's ROIC performance for the year ended December 31, 2018 relative to a target rate (the "2018 ROIC Target") set forth in the award agreement. Vesting is subject to INSW's Human Resources and Compensation Committee's certification of achievement of the performance measure and target no later than March 31, 2019. | ||||||
Performance Shares [Member] | Executive Officer [Member] | February 14 2017 [Member] | |||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||
Granted | 11,882 | ||||||
TSR [Member] | Senior Officers [Member] | |||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||
Weighted average grant date fair value per share | $ 18.87 | ||||||
Stock Compensation Plan [Member] | Senior Officers [Member] | |||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||
Granted, options | 124,955 | ||||||
Grants, options, per share | $ 7.76 | ||||||
Share Price | $ 17.46 | $ 17.46 | |||||
Fair value assumptions, method used | Black-Scholes option pricing model | ||||||
Fair value assumptions, risk free interest rate | 2.67% | ||||||
Fair value assumptions, expected dividend rate | 0.00% | ||||||
Fair value assumptions, expected volatility factor | 0.42% | ||||||
Fair value assumptions, expected life | 6 years | ||||||
Restricted Stock Units (RSUs) [Member] | |||||||
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||
Shares paid for tax withholding for share based compensation | 589 | 969 | 23,013 | 13,961 | |||
Shares paid for tax withholding for share based compensation, per share amount | $ 21.48 | $ 19.69 | $ 17.81 | $ 18.66 |