Stock-Based Compensation	9 Months Ended
Stock-Based Compensation	Sep. 30, 2023
Stock-Based Compensation [Abstract]
Stock-Based Compensation	Note 9 - Stock-Based Compensation We recognize compensation expense on a pro rata straight-line basis over the requisite service period for stock-based compensation awards with both graded and cliff vesting terms. We recognize the cumulative effect of a change in the number of awards expected to vest in compensation expense in the period of change. We have not capitalized any portion of our stock-based compensation. Our forfeiture rate is based on actuals. During the three months ended September 30, 2023 and 2022, we recognized $0.3 million and $0.5 million of stock-based compensation expense related to RSU and PRSU awards, respectively, under the fair value method. We recognized $0.9 million and $1.5 million of stock-based compensation expense related to RSU and PRSU awards for the nine months ended September 30, 2023 and 2022, respectively. During the three and nine months ended September 30, 2023, we granted approximately 45,455 and 90,782 time-based restricted stock units (“RSUs”) with an aggregate fair value of approximately $0.1 million and $0.3 million, respectively. During the nine months ended September 30, 2022, we granted approximately 96,025 time-based RSUs with an aggregate fair value of approximately $1.5 million. We granted no time-based RSUs during the three months ended September 30, 2022. During the three months ended September 30, 2023 and 2022, we vested approximately 54,999 and 11,299 RSUs, respectively. During the nine months ended September 30, 2023 and 2022, we vested approximately 98,446 and 49,281 RSUs, respectively. Typically RSUs vest quarterly in equal amounts over the course of one to three years. GSE’s 1995 long-term incentive program (“LTIP”) provides for the issuance of performance-vesting and time-vesting RSUs to certain executives and employees. Vesting of the performance-vesting restricted stock units (“PRSU”) is contingent upon the employee’s continued employment and the Company’s achievement of certain performance goals during designated performance periods as established by the Compensation Committee of the Company’s Board of Directors. We recognize compensation expense, net of estimated forfeitures, for PRSUs on a straight-line basis over the performance period based on the probable outcome of achievement of the financial targets. At the end of each reporting period, we estimate the number of PRSUs that are expected to vest, based on the probability and extent to which the performance goals will be met, and take into account these estimates when calculating the expense for the period. If the number of shares expected to be earned changes during the performance period, we make a cumulative adjustment to compensation expense based on the revised number of shares expected to be earned. During the nine months ended September 30, 2023, we granted approximately 59,767 PRSU’s. These grants are subject to multiple vesting criteria including reaching a 20-day VWAP of $15.00 prior to the expiration of the awards, and a time-vesting restriction, which will vest in equal parts over the next 18 quarters. During the nine months ended September 30, 2022, there were 80,000 PRSUs granted, including 20,000 cash-settled grants to employees. These grants are subject to multiple vesting criteria including reaching a 20-day VWAP of $19.40 prior to the expiration of the awards, and a time-vesting restriction, which will vest in equal portions over the next 15 quarters ending December 31, 2025. There were no PRSUs granted during the three months ended September 30, 2023 or September 30, 2022. During the nine months ended September 30, 2023 and 2022, we vested 15,000 PRSUs, of which, 3,750 PRSUs were cash-settled, respectively. The market vesting criteria for the Q1 2022 PRSU grant was achieved in April 2022 for the 80,000 PRSUs which will fully vest over the next 9 quarters. We did not grant any stock options for the nine months ended September 30, 2023 and 2022.