Concentration of Risk - Additional Information (Detail)	Mar. 31, 2015 CommercialBank Restaurants	Mar. 31, 2014 Restaurants
Risks and Uncertainties [Abstract]
Number of restaurants leased to Del Taco	6	6
Commercial bank	1dtrpi_NumberOfMajorCommercialBanks

The number of units (items of property) under operating lease arrangements.

No definition available.

Name:	us-gaap_PropertySubjectToOrAvailableForOperatingLeaseNumberOfUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant