Goodwill and Other Intangible Assets - Additional Information (Detail)	9 Months Ended
Sep. 30, 2020 USD ($)
Goodwill [Line Items]
Impairment of goodwill	$ 0
Accumulated goodwill impairment losses	0
Consulting [Member]
Goodwill [Line Items]
Goodwill allocated to reporting unit	$ 8,000,000.0

Amount of accumulated impairment loss for 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 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121556970&loc=d3e13816-109267

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Amount of loss from the write-down of an asset representing the 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
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 2
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Amount of goodwill allocated to reporting unit with zero or negative amount of net assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 20
-Section 50
-Paragraph 1A
-URI http://asc.fasb.org/extlink&oid=121556970&loc=SL108378252-109267

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