Contingencies (Details) $ in Millions	Feb. 18, 2016 item	Sep. 30, 2016 USD ($)
Contingencies
Number of affiliated mutual fund trustees involved in litigation	2
Number of mutual fund shareholders involved in litigation	3
Accured contingencies related to other matters \| $		$ 3.0

Amount of loss contingency liability.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=25496072&loc=d3e14326-108349

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