Agreements and Related Party Transactions - Sub-Administration and Expense Support (Details) - Sub-Administration Agreement	Oct. 01, 2018
Related Party Transaction [Line Items]
Related party transaction, initial term	2 years
Related party transaction, renewal term	1 year
Termination notice period	120 days

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.

No definition available.

Name:	us-gaap_RelatedPartyTransactionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration