Employee Benefit Plans	12 Months Ended
Dec. 31, 2021
Compensation And Retirement Disclosure [Abstract]
Employee Benefit Plans	17. EMPLOYEE BENEFIT PLANS Retirement Savings and Profit Sharing Plan We maintain a defined contribution 401(k) retirement savings plan which is available to all employees who have worked greater than 1,000 hours within a fiscal year. Under the plan, an eligible employee may elect to defer receipt of a portion of their annual pay, including salary and bonus. During 2021, 2020 and 2019, we contributed this amount to the plan on the employee’s behalf and also made a matching contribution equal to 50% of the first 2% and 25% of the next 4% of the percentage of annual pay that the employee elected to defer. For employees hired on or after January 1, 2020, the participant is 100% vested in the company’s matching contribution after two years of service. Employees hired before January 1, 2020 are fully vested in the company’s matching contribution. During the years ended December 31, 2021, 2020 and 2019, we recorded expense under this plan of approximately $3.0 million, $3.0 million, and $2.6 million, respectively. Employee Stock Purchase Plan We maintain an employee stock purchase plan that allows substantially all full-time and part-time employees to acquire shares of our common stock through payroll deductions over three-month offering periods. The per share purchase price is equal to 95% of the fair market value of a share of our common stock on the last day of the offering period, and purchases are limited to 10% of an employee’s salary, up to a maximum of $25,000 per calendar year. We are authorized to issue up to 4.0 million shares of common stock under the employee stock purchase plan, and, as of December 31, 2021, 3.4 million shares of common stock have been issued under the plan. The compensation expense for employee share purchases recorded during the years ended December 31, 2021, 2020 and 2019 in connection with the compensatory elements of our employee stock purchase plan was not significant.

Employee Benefit Plans

12 Months Ended

Dec. 31, 2021

Compensation And Retirement Disclosure [Abstract]

17. EMPLOYEE BENEFIT PLANS

Retirement Savings and Profit Sharing Plan

We maintain a defined contribution 401(k) retirement savings plan which is available to all employees who have worked greater than 1,000 hours within a fiscal year. Under the plan, an eligible employee may elect to defer receipt of a portion of their annual pay, including salary and bonus. During 2021, 2020 and 2019, we contributed this amount to the plan on the employee’s behalf and also made a matching contribution equal to 50% of the first 2% and 25% of the next 4% of the percentage of annual pay that the employee elected to defer. For employees hired on or after January 1, 2020, the participant is 100% vested in the company’s matching contribution after two years of service. Employees hired before January 1, 2020 are fully vested in the company’s matching contribution. During the years ended December 31, 2021, 2020 and 2019, we recorded expense under this plan of approximately $3.0 million, $3.0 million, and $2.6 million, respectively.

Employee Stock Purchase Plan

We maintain an employee stock purchase plan that allows substantially all full-time and part-time employees to acquire shares of our common stock through payroll deductions over three-month offering periods. The per share purchase price is equal to 95% of the fair market value of a share of our common stock on the last day of the offering period, and purchases are limited to 10% of an employee’s salary, up to a maximum of $25,000 per calendar year. We are authorized to issue up to 4.0 million shares of common stock under the employee stock purchase plan, and, as of December 31, 2021, 3.4 million shares of common stock have been issued under the plan.

The compensation expense for employee share purchases recorded during the years ended December 31, 2021, 2020 and 2019 in connection with the compensatory elements of our employee stock purchase plan was not significant.