Stock-Based Compensation	12 Months Ended
Dec. 31, 2021
Stock-Based Compensation [Abstract]
Stock-Based Compensation	15. Stock-Based Compensation During the years ended December 31, 2021, 2020 and 2019, we granted performance share units (which we refer to as “PSUs”) covering up to 0.2 million, 0.3 million, and 0.3 million shares of common stock, respectively in each year, assuming maximum level of performance, with grant date fair values of $58.28, $26.38, and $22.01, respectively, per share that are subject to both service and performance vesting conditions. The quantity of shares that will ultimately vest for the PSUs ranges from 0% to 250% of a targeted number of shares for each participant and will be determined based on an achievement of a three year pre-tax income performance goal. During the year ended December 31, 2021, 0.3 million PSUs of common stock vested that were granted in 2018. Approximately 0.8 million shares will vest in 2022 to 2024 if the defined maximum performance targets are met, and no shares will vest if the defined minimum performance targets are not met. During the years ended December 31, 2021, 2020 and 2019, we also granted restricted stock units (which we refer to as “RSUs”) covering 0.2 million, 0.4 million and 0.6 million shares of common stock, respectively, with grant date fair values of $53.21, $30.44 and $23.85 per share, respectively, that vest over a 1 to 3 year period. During the year ended December 31, 2021, we granted 7.0 thousand shares of common stock on an unrestricted basis (which we refer to as “stock awards”) with grant date fair values of $78.30 to our non-employee directors.The following table summarizes the activity of our PSUs, RSUs, and stock awards for the years ended December 31, 2021, 2020 and 2019 (in thousands): Year Ended December 31, 2021 2020 2019 Shares Weighted average per share grant date fair value Shares Weighted average per share grant date fair value Shares Weighted average per share grant date fair value Outstanding, beginning of year 1,462 $ 26.76 1,219 $ 24.64 846 $ 25.14Granted 347 55.60 701 28.90 882 23.49Vested (675) 29.31 (454) 24.42 (430) 23.53Forfeited (30) 37.68 (4) 28.56 (79) 24.99Outstanding, end of year 1,104 $ 31.48 1,462 $ 26.76 1,219 $ 24.64 A summary of our outstanding RSUs and PSUs, assuming current estimated level of performance achievement, are as follows (in thousands, except years): As of December 31, 2021Unvested units 1,104Unrecognized compensation cost $ 17,206Weighted-average period to recognize compensation cost 1.69During the years ended December 31, 2021, 2020 and 2019, the Company recognized stock-based compensation expense of $14.4 million, $18.3 million and $15.3 million, respectively, which is generally included in selling, general and administrative on the consolidated statements of operations.

Stock-Based Compensation

12 Months Ended

Dec. 31, 2021

15. Stock-Based Compensation During the years ended December 31, 2021, 2020 and 2019, we granted performance share units (which we refer to as “PSUs”) covering up to 0.2 million, 0.3 million, and 0.3 million shares of common stock, respectively in each year, assuming maximum level of performance, with grant date fair values of $58.28, $26.38, and $22.01, respectively, per share that are subject to both service and performance vesting conditions. The quantity of shares that will ultimately vest for the PSUs ranges from 0% to 250% of a targeted number of shares for each participant and will be determined based on an achievement of a three year pre-tax income performance goal. During the year ended December 31, 2021, 0.3 million PSUs of common stock vested that were granted in 2018. Approximately 0.8 million shares will vest in 2022 to 2024 if the defined maximum performance targets are met, and no shares will vest if the defined minimum performance targets are not met. During the years ended December 31, 2021, 2020 and 2019, we also granted restricted stock units (which we refer to as “RSUs”) covering 0.2 million, 0.4 million and 0.6 million shares of common stock, respectively, with grant date fair values of $53.21, $30.44 and $23.85 per share, respectively, that vest over a 1 to 3 year period. During the year ended December 31, 2021, we granted 7.0 thousand shares of common stock on an unrestricted basis (which we refer to as “stock awards”) with grant date fair values of $78.30 to our non-employee directors.The following table summarizes the activity of our PSUs, RSUs, and stock awards for the years ended December 31, 2021, 2020 and 2019 (in thousands): Year Ended December 31, 2021 2020 2019 Shares Weighted average per share grant date fair value Shares Weighted average per share grant date fair value Shares Weighted average per share grant date fair value Outstanding, beginning of year 1,462 $ 26.76 1,219 $ 24.64 846 $ 25.14Granted 347 55.60 701 28.90 882 23.49Vested (675) 29.31 (454) 24.42 (430) 23.53Forfeited (30) 37.68 (4) 28.56 (79) 24.99Outstanding, end of year 1,104 $ 31.48 1,462 $ 26.76 1,219 $ 24.64 A summary of our outstanding RSUs and PSUs, assuming current estimated level of performance achievement, are as follows (in thousands, except years): As of December 31, 2021Unvested units 1,104Unrecognized compensation cost $ 17,206Weighted-average period to recognize compensation cost 1.69During the years ended December 31, 2021, 2020 and 2019, the Company recognized stock-based compensation expense of $14.4 million, $18.3 million and $15.3 million, respectively, which is generally included in selling, general and administrative on the consolidated statements of operations.