Share-Based Compensation (Narrative) (Details) $ / shares in Units, $ in Millions	6 Months Ended
	Jun. 30, 2023 USD ($) d $ / shares shares	Jun. 30, 2022 $ / shares shares	Dec. 31, 2022 shares
Restricted Stock And Restricted Stock Unit (RSU)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	291,159	132,117
Restricted Stock And Restricted Stock Unit (RSU) | Board of Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting periods	1 year
Restricted Stock And Restricted Stock Unit (RSU) | Chief Executive Officer
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting periods	8 years
Market-based Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)	167,606	100,193
Trading days | d	20
Trading days, lookback | d	30
Weighted-average grant-date fair values of restricted stock awards granted (in usd per share) | $ / shares	$ 70.07	$ 87.11
Weighted-average period to recognize compensation cost (in years)	2 years 2 months 12 days
Restricted Stock, Restricted Stock Unit (RSU), Market-based Restricted Stock
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unrecognized compensation cost related to non-vested awards granted | $	$ 58.9
Restricted Stock Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, non-option equity instruments, outstanding, number	849,826		464,354
Granted (in shares)	458,765
Weighted-average period to recognize compensation cost (in years)	3 years
ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum issuance of common stock (in shares)	2,000,000
Market value of common stock (as a percent)	85.00%
Number of shares available for issuance (in shares)	1,068,601
Maximum earnings withheld by the employees (as a percent)	15.00%
Estimated forfeiture rate	12.70%	11.20%
Issuance of shares under employee stock purchase plan (in shares)	87,098	76,741
Minimum | Restricted Stock And Restricted Stock Unit (RSU) | Senior Staff
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting periods	4 years
Minimum | Market-based Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair values of restricted stock awards granted (in usd per share) | $ / shares	$ 83.61	$ 107.97
Maximum | Restricted Stock And Restricted Stock Unit (RSU) | Senior Staff
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting periods	5 years
Maximum | Market-based Restricted Stock Awards
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted-average grant-date fair values of restricted stock awards granted (in usd per share) | $ / shares	$ 103.76	138.73
2015 Stock Option Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum issuance of common stock (in shares)	4,200,000
Number of options outstanding (in shares)	435,135
Number of shares available for issuance (in shares)	1,043,255
2015 Stock Option Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Market value of common stock (as a percent)	100.00%
Employee Stock Purchase Plan | ESPP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Per share price of shares purchased (in dollars per share) | $ / shares	$ 54.25	$ 68.22