Subsequent Events - Additional Information (Detail) (Subsequent Event, Cash Distribution, USD $)	1 Months Ended
Jul. 24, 2013
Subsequent Event \| Cash Distribution
Subsequent Event [Line Items]
Declaration of cash distribution	$ 0.485
Distribution declaration date	Jul. 24, 2013
Distribution payment date	Aug. 14, 2013
Distribution record date	Aug. 07, 2013

Date of distribution for distribution of cash, stock, or units to a member or limited partner of limited liability company (LLC) or limited partnership (LP), in CCYY-MM-DD format.

No definition available.

Name:	us-gaap_DistributionMadeToMemberOrLimitedPartnerDistributionDate1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration