Share-based payments	9 Months Ended
	Sep. 30, 2022
Share-Based Payment Arrangement [Abstract]
Share-based payments	Share-based payments. As part of its incentive compensation program for executives and senior management employees, the Company provides share-based awards, which usually include a combination of time-based restricted stock units, performance-based restricted stock units and stock options. Each restricted stock unit represents a contractual right to receive a share of the Company's common stock. The time-based units generally vest on each of the first three anniversaries of the grant date, while the performance-based units vest upon achievement of certain financial objectives and an employee service requirement over a period of approximately three years. The stock options vest on each of the first three anniversaries of the grant date at a rate of 20%, 30% and 50%, chronologically, and expire 10 years after the grant date. Each vested stock option can be exercised to purchase a share of the Company's common stock at the strike price set by the Company at the grant date. The compensation expense associated with the share-based awards is calculated based on the fair value of the related award and recognized over the corresponding vesting period.During the first nine months of 2022, the Company granted time-based and performance-based restricted stock units with an aggregate grant-date fair value of $11.7 million (183,000 units with an average grant price per unit of $63.68). During the first nine months of 2021, the aggregate grant-date fair values of restricted stock unit and stock option awards, respectively, were $9.2 million (170,000 units with an average grant price per unit of $53.70) and $1.3 million (141,000 options with an average grant price per option of $9.24 and exercise strike price of $53.24).