Summary of Significant Accounting Policies - Provisions, Employee Benefits, Income Taxes and Dividends (Details) - USD ($) $ in Thousands |
12 Months Ended | ||||
|---|---|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||
| Provision for loss making voyages in progress | $ 2,631 | $ 3,129 | |||
| Revenue | 463,049 | 419,782 | $ 480,820 | ||
| Termination of indemnities liability | 1,336 | 1,127 | |||
| Dividends paid to common stockholders | 0 | 0 | 19,325 | ||
| Dividends paid to preferred stockholders | 0 | 3,681 | 16,025 | ||
| Income tax benefit/(expense) | $ 3,192 | (1,265) | 3,154 | ||
| Severance and retirement compensation plan | |||||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||
| Description of defined contribution pension and other postretirement plans | The amount of compensation is based on the number of years of service and the amount of remuneration at the date of dismissal or retirement up to a maximum of two years' salary. If the employees remain in the employment of the Company until normal retirement age, they are entitled to retirement compensation which is equal to 40% of the compensation amount that would be payable if they were dismissed at that time. The number of employees that will remain with the Company until retirement age is not known. | ||||
| Defined Benefit Plan, Funded Percentage | 40.00% | ||||
| Argentina | |||||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||
| Effective Income Tax Rate Continuing Operations | 35.00% | ||||
| Argentina | Tax Reform | |||||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||
| Effective Income Tax Rate Continuing Operations | 25.00% | 30.00% | |||
| Income tax benefit/(expense) | $ 2,837 | ||||
| US Retirement Savings Plan | |||||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||
| Description of defined contribution pension and other postretirement plans | The Company sponsors a 401(k) retirement savings plan, which is categorized as a defined contribution plan. The plan is available to full time employees who meet the plan's eligibility requirements. The plan permits employees to make contributions up to 15% of their annual salary with the Company matching up to the first 6%. The Company makes monthly contributions (matching contributions) to the plan based on amounts contributed by employees. Subsequent to making the matching contributions, the Company has no further obligations. The Company may make an additional discretionary contribution annually if such a contribution is authorized by the Board of Directors. The plan is administered by an independent professional firm that specializes in providing such services. | ||||
| Pooling arrangements | |||||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||
| Revenue | $ 8,041 | $ 15,115 | $ 1,825 | ||
| Minimum | Stock-Based Compensation | |||||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||
| Vesting Period | 3 years | ||||
| Maximum | Stock-Based Compensation | |||||
| Share Based Compensation Arrangement By Share Based Payment Award [Line Items] | |||||
| Vesting Period | 4 years | ||||