Stock Transactions And Stock-Based Compensation (Details) $ / shares in Units, $ in Millions			12 Months Ended
	Dec. 23, 2021 USD ($) shares	Dec. 31, 2019 shares	Dec. 31, 2023 USD ($) vote $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, shares authorized (in shares)			500,000,000.0	500,000,000
Common stock, par value (in USD per share) | $ / shares			$ 0.01	$ 0.01
Preferred shares authorized (in shares)			15,000,000.0	15,000,000
Preferred shares outstanding (in shares)			0	0
Preferred shares issued (in shares)			0	0
Common stock voting rights (in votes per share) | vote			1
Total unrecognized compensation cost related to RSUs/PSUs | $			$ 27.5
Granted (in shares)			1,000,000.0	600,000	500,000
Unvested (in shares)			1,700,000	1,500,000	1,700,000	1,900,000
Expected forfeiture rate			12.00%	6.00%	6.00%
Period of recognition			1 year
Aggregate intrinsic value of options exercised | $			$ 9.0	$ 31.0	$ 33.0
Employee service share-based compensation, tax benefit from exercise of stock options | $			$ 3.6	$ 7.2	6.7
Share withheld (in shares)			214,800	192,400
Tax withholding payment related to net settlement of equity awards | $			$ 7.9	$ 9.1	7.2
RSUs / PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee service share-based compensation, tax benefit from exercise of stock options | $			$ 1.0	$ 1.0	$ 1.0
RSUs / PSUs | Pacific Dental Services
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period	4 years
Total unrecognized compensation cost related to RSUs/PSUs | $	$ 12.5
Granted (in shares)	273,522
Unvested (in shares)			273,522
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield			0.00%	0.00%	0.00%
Employee service share-based compensation, tax benefit from exercise of stock options | $			$ 1.0	$ 4.0	$ 4.0
2019 Omnibus Incentive Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares authorized under the Stock Plan (in shares)		21,000,000
Award expiration period		10 years
2019 Omnibus Incentive Plan | Minimum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
2019 Omnibus Incentive Plan | Minimum | RSUs / PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		3 years
2019 Omnibus Incentive Plan | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		5 years
2019 Omnibus Incentive Plan | Maximum | RSUs / PSUs
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period		5 years