S000001470 [Member] Expense Example - BATS: Mortgage Total Return Series - BATS: Mortgage Total Return Series	Mar. 31, 2026 USD ($)
Prospectus [Line Items]
Expense Example, with Redemption, 1 Year	$ 0
Expense Example, with Redemption, 3 Years	0
Expense Example, with Redemption, 5 Years	0
Expense Example, with Redemption, 10 Years	$ 0

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form N-1A
-Section 3
-Subsection instruction
-Paragraph 4

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Namespace Prefix:	oef_
Data Type:	dtr-types:nonNegativeMonetaryItemType
Balance Type:	na
Period Type:	duration

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form N-1A
-Section 3
-Subsection instruction
-Paragraph 4

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Namespace Prefix:	oef_
Data Type:	dtr-types:nonNegativeMonetaryItemType
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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form N-1A
-Section 3
-Subsection instruction
-Paragraph 4

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Namespace Prefix:	oef_
Data Type:	dtr-types:nonNegativeMonetaryItemType
Balance Type:	na
Period Type:	duration

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form N-1A
-Section 3
-Subsection instruction
-Paragraph 4

Name:	oef_ExpenseExampleYear10
Namespace Prefix:	oef_
Data Type:	dtr-types:nonNegativeMonetaryItemType
Balance Type:	na
Period Type:	duration

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Form N-1A
-Section 1
-Subsection a

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Namespace Prefix:
Data Type:	na
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