Organization - Additional Information (Detail)	Dec. 31, 2018
General Partner [Member]
Subsidiary of Limited Liability Company or Limited Partnership [Line Items]
Required interest in the equity of each Partnership	1.00%

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