Investments - Other Details (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Securities required to be held with various regulatory authorities as required by law	$ 210.8	$ 188.6
Fair value of assets on deposit in collateral agreements	367.1	358.5
Carrying value of assets on deposit in collateral agreements	352.0	$ 368.0
Insurance Operations, U.K. \| Discontinued operation
Cash And Securities Deposited	10.4
Letters Of Credit And Securities Placed	$ 23.2

Represents the carrying value of assets on deposit in collateral agreements.

No definition available.

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- Definition

Represents the fair value of assets on deposit in collateral agreements.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

The amount of cash and securities deposited to meet Funds at Lloyd’s (FAL) obligations in respect of the Syndicate, as per the terms of the sale agreement.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

The amount of Letters of credit and securities placed to meet Funds at Lloyd’s (FAL) obligations in respect of the Syndicate, as per the terms of the sale agreement.

+ References

No definition available.

+ Details

Name:	pros_LettersOfCreditAndSecuritiesPlaced
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount of cash and investment securities on deposit with state regulatory authorities in connection with capital requirements.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 825
-Section 50
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=75763970&loc=SL75763979-209797

+ Details

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Balance Type:	debit
Period Type:	instant

- Details

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- Details

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