Goodwill and Other Intangibles - Goodwill Rollforward (Details) $ in Thousands	6 Months Ended
Jun. 30, 2020 USD ($)
Goodwill
Goodwill, beginning balance	$ 934,688
Foreign currency translation adjustments	(1,573)
Allocation of goodwill based on portion of Investment Management business sold (Note 3)	(34,273)
Goodwill, ending balance	898,842
Real Estate
Goodwill
Goodwill, beginning balance	871,081
Foreign currency translation adjustments	(1,573)
Allocation of goodwill based on portion of Investment Management business sold (Note 3)	0
Goodwill, ending balance	869,508
Investment Management
Goodwill
Goodwill, beginning balance	63,607
Foreign currency translation adjustments	0
Allocation of goodwill based on portion of Investment Management business sold (Note 3)	(34,273)
Goodwill, ending balance	$ 29,334

Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(10)(1))
-URI http://asc.fasb.org/extlink&oid=120398452&loc=d3e534808-122878

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 45
-Paragraph 5
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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-SubTopic 20
-Section 45
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- Definition

Amount of foreign currency translation gain (loss) which increases (decreases) an asset representing future economic benefits from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Topic 350
-SubTopic 20
-Section 50
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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

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Amount of divestiture of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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