Share-based Payments (Summary of Stock Option Activity) (Details) $ / shares in Units, $ in Millions	3 Months Ended	9 Months Ended
	Mar. 31, 2023 USD ($) $ / shares shares	Sep. 30, 2023 USD ($) $ / shares shares
Stock options and ESPP
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance (in shares) | shares	2,730,295	2,730,295
Granted (in shares) | shares		262,725
Assumed in IAA acquisition (Note 5) (in shares) | shares		187,727
Exercised (in shares) | shares		(351,349)
Forfeited/Expired (in shares) | shares		(135,497)
Ending balance (in shares) | shares		2,693,901
Exercisable (in shares) | shares		1,808,780
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Beginning balance, Weighted average exercise price (usd per share) | $ / shares	$ 46.88	$ 46.88
Granted, Weighted average exercise price (usd per share) | $ / shares		58.09
Assumed in acquisition, Weighted average exercise price (usd per share) | $ / shares		50.96
Exercised, Weighted average exercise price (usd per share) | $ / shares		44.19
Forfeited/Expired, Weighted average exercise price (usd per share) | $ / shares		54.44
Ending balance, Weighted average exercise price (usd per share) | $ / shares		48.23
Exercisable, Weighted average exercise price (usd per share) | $ / shares		$ 43.55
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, Weighted average remaining contractual life (in years)	7 years 3 months 18 days	6 years 10 months 24 days
Exercisable, Weighted average remaining contractual life (in years)		6 years 1 month 6 days
Outstanding beginning balance, Aggregate intrinsic value | $	$ 31.2	$ 31.2
Exercised, Aggregate intrinsic value | $		5.6
Outstanding ending balance, Aggregate intrinsic value | $		39.0
Exercisable, Aggregate intrinsic value | $		$ 34.5
Premium-priced stock options
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding [Roll Forward]
Beginning balance (in shares) | shares	1,118,432	1,118,432
Granted (in shares) | shares		0
Assumed in IAA acquisition (Note 5) (in shares) | shares		0
Exercised (in shares) | shares		0
Forfeited/Expired (in shares) | shares		(171,065)
Ending balance (in shares) | shares		947,367
Exercisable (in shares) | shares		45,757
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]
Beginning balance, Weighted average exercise price (usd per share) | $ / shares	$ 91.26	$ 91.26
Granted, Weighted average exercise price (usd per share) | $ / shares		0
Assumed in acquisition, Weighted average exercise price (usd per share) | $ / shares		0
Exercised, Weighted average exercise price (usd per share) | $ / shares		0
Forfeited/Expired, Weighted average exercise price (usd per share) | $ / shares		91.25
Ending balance, Weighted average exercise price (usd per share) | $ / shares		91.26
Exercisable, Weighted average exercise price (usd per share) | $ / shares		$ 91.37
Share-Based Compensation Arrangement by Share-Based Payment Award, Options, Additional Disclosures [Abstract]
Outstanding, Weighted average remaining contractual life (in years)	4 years 8 months 12 days	3 years 10 months 24 days
Exercisable, Weighted average remaining contractual life (in years)		3 years 10 months 24 days