Goodwill and Intangible Assets, net - Narrative (Details) $ in Millions	Mar. 31, 2020 USD ($)
Benefit Consultants Group Inc.
Goodwill [Line Items]
Acquired finite-lived intangible assets	$ 14.1
NTA
Goodwill [Line Items]
Acquired finite-lived intangible assets	$ 160.4

The amount of identifiable intangible assets recognized as of the acquisition date.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 55
-Paragraph 37
-URI http://asc.fasb.org/extlink&oid=116868840&loc=d3e2207-128464

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=116869197&loc=d3e4845-128472

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant