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Fair Value of Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Balance Sheet Grouping, Financial Statement Captions
Carrying value	$ 294.7	$ 283.5
NSM Holding Co LLC
Balance Sheet Grouping, Financial Statement Captions
Carrying value	218.4	219.2
NSM Holding Co LLC | NSM Bank Facility
Balance Sheet Grouping, Financial Statement Captions
Carrying value	217.1	217.4
NSM Holding Co LLC | Carrying Value | NSM Bank Facility
Balance Sheet Grouping, Financial Statement Captions
Carrying value	217.1	217.4
NSM Holding Co LLC | Estimate of Fair Value Measurement | NSM Bank Facility
Balance Sheet Grouping, Financial Statement Captions
Debt Instrument, Fair Value Disclosure	208.7	221.2
NSM Holding Co LLC | Estimate of Fair Value Measurement | Other NSM
Balance Sheet Grouping, Financial Statement Captions
Debt Instrument, Fair Value Disclosure	1.6	1.7
Kudu | Kudu Debt [Member]
Balance Sheet Grouping, Financial Statement Captions
Carrying value	65.7	53.6
Kudu | Estimate of Fair Value Measurement | Kudu Debt [Member]
Balance Sheet Grouping, Financial Statement Captions
Debt Instrument, Fair Value Disclosure	63.4	53.6
Other Operations | Carrying Value
Balance Sheet Grouping, Financial Statement Captions
Carrying value		10.7
Other Operations | Estimate of Fair Value Measurement
Balance Sheet Grouping, Financial Statement Captions
Debt Instrument, Fair Value Disclosure	11.3	11.3
Term Loan | NSM Holding Co LLC | NSM Bank Facility
Balance Sheet Grouping, Financial Statement Captions
Carrying value	220.7
Term Loan | NSM Holding Co LLC | Other NSM
Balance Sheet Grouping, Financial Statement Captions
Carrying value	$ 1.3	$ 1.8

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

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-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

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-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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-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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