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Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	$ 283.5	$ 192.7
NSM Holding Co LLC
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	219.2	178.5
NSM Holding Co LLC | Fair value | NSM Bank Facility
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	221.2	176.1
NSM Holding Co LLC | Fair value | Other NSM
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	1.7	1.9
Kudu | Kudu Debt
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	53.6
MediaAlpha
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	0.0	14.2
MediaAlpha | MediaAlpha Bank Facility
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	0.0	14.2
MediaAlpha | Fair value | MediaAlpha Bank Facility
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	0.0	14.6
MediaAlpha | Carrying Value | MediaAlpha Bank Facility
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	0.0	14.2
Other Operations | Fair value
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt, fair value	11.3	0.0
Other Operations | Carrying Value
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt		0.0
Term Loan | NSM Holding Co LLC | NSM Bank Facility
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	217.4	176.6
Term Loan | NSM Holding Co LLC | Other NSM
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	1.8	1.9
Term Loan | NSM Holding Co LLC | Carrying Value | NSM Bank Facility
Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt	$ 217.4	$ 176.6

X

- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13433-108611

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+ References

No definition available.

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- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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-Name Accounting Standards Codification
-Topic 210
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-Section S99
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