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Debt - Schedule of the Change in Debt under the NSM Bank Facility (Details) £ in Millions, $ in Millions				12 Months Ended
	Apr. 07, 2020 USD ($)	Apr. 07, 2020 GBP (£)	Apr. 01, 2019 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 GBP (£)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Debt Instrument
Beginning balance				$ 283.5
Repayment of debt and revolving lines of credit				(4.5)		$ (22.9)	$ (15.4)
Ending balance				376.4		283.5
NSM
Debt Instrument
Beginning balance				219.2
Ending balance				272.6		219.2
NSM | Embrace Pet Insurance
Debt Instrument
Borrowings			$ 20.4
NSM | NSM Bank Facility
Debt Instrument
Beginning balance				221.3		180.4
Ending balance				277.4		221.3	$ 180.4
NSM | NSM Bank Facility | Term Loan
Debt Instrument
Beginning balance				217.4
Borrowings	$ 52.4	£ 42.5		52.4	£ 42.5	42.9
Repayment of debt and revolving lines of credit				(2.0)		(2.0)
Foreign currency translation				5.7		0.0
Ending balance				271.3		217.4
NSM | NSM Bank Facility | Term Loan | Kingsbridge
Debt Instrument
Borrowings				52.4
NSM | NSM Bank Facility | Term Loan | Embrace Pet Insurance
Debt Instrument
Borrowings						20.4
NSM | NSM Bank Facility | Term Loan | Renewal rights
Debt Instrument
Borrowings						22.5
NSM | NSM Bank Facility | Revolving Credit Facility
Debt Instrument
Borrowings				0.0		6.5
Repayment of debt and revolving lines of credit				$ 0.0		$ (6.5)

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- Definition

Amount of increase (decrease) in debt instruments, classified as other.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The cash inflow during the period from additional borrowings in aggregate debt. Includes proceeds from short-term and long-term debt.

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