Transactions With Del Taco - Additional Information (Detail)	6 Months Ended
Jun. 30, 2013 Acquisition
Related Party Transactions [Abstract]
Number of other partnerships formed for acquisition	3

Number of other partnerships formed for acquisition.

No definition available.

Name:	dtipiv_NumberOfOtherPartnershipsFormedForAcquisition
Namespace Prefix:	dtipiv_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration