Concentration of Risk - Additional Information (Detail)	Sep. 30, 2015 Restaurants CommercialBank	Sep. 30, 2014 Restaurants
Risks and Uncertainties [Abstract]
Number of restaurants leased to Del Taco	6	6
Commercial bank \| CommercialBank	1

Number of major commercial banks the partnership maintains substantially all of its cash and cash equivalents.

No definition available.

Name:	dtrpi_NumberOfMajorCommercialBanks
Namespace Prefix:	dtrpi_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant