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Variable Interest Entities - Investment Products (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
SEI-Sponsored Open-Ended Money Market Mutual Funds [Member]
Financial Support for Nonconsolidated Legal Entity [Line Items]
Fees waived according to expense limitation agreements	$ 6,942	$ 9,145	$ 20,620	$ 31,513

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

Amount of financial support provided to a nonconsolidated legal entity that is required to comply with or operate in accordance with requirements that are similar to those included in Rule 2a-7 of the Investment Company Act of 1940 for registered money market funds.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 946
-SubTopic 20
-Section 50
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66023616&loc=SL35737432-115832

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 15
-Paragraph 12
-Subparagraph (f)(2)
-URI http://asc.fasb.org/extlink&oid=66022390&loc=d3e923-111674

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