Subsequent Event - Additional Information (Detail) - Subsequent Event [Member] - USD ($) $ / shares in Units, $ in Millions	Dec. 01, 2017	Oct. 31, 2017
Manning and Napier Group LLC and Rainier Investment Management LLC [Member]
Subsequent Event [Line Items]
Business combination, assets acquired and liabilities assumed, assets	$ 122.0
Business combination, agreement date	May 11, 2017
Business combination, cash paid	$ 1.0
Business acquisition, effective date of acquisition	Dec. 01, 2017
Dividend Declared [Member]
Subsequent Event [Line Items]
Dividend to be paid		$ 0.075
Dividend declared date		Oct. 31, 2017
Dividend record date		Nov. 15, 2017
Dividend payable date		Dec. 08, 2017

Date when the business acquisition agreement was executed, in CCYY-MM-DD format.

No definition available.

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- Definition

Date when the acquirer obtains control of the acquiree, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 25
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=84229725&loc=d3e845-128460

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-Section 50
-Paragraph 2
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-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

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- Definition

Amount of assets acquired at the acquisition date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (c)
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- Definition

Date the declared dividend will be paid, in CCYY-MM-DD format.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

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- Definition

The per share amount of a dividend declared, but not paid, as of the financial reporting date.

+ References

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- Definition

Date the dividend to be paid was declared, in CCYY-MM-DD format.

+ References

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- Definition

Date the holder must own the stock to be entitled to the dividend, in CCYY-MM-DD format.

+ References

No definition available.

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- Definition

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
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- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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