B737-700 captain reported a track deviation occurred during a route offset to avoid wake turbulence.

Narrative:

I was pilot flying on flight to hou. We were cleared to descend via the kiddz 3 arrival; landing runway 31. I believe around the kiddz intersection; we started to encounter mild wake turbulence from company aircraft approximately 10 miles in front of us. I went into the FMC and programmed a .1L offset to stay out of his wake. I did not enter a start or end waypoint for the offset. Sometime later; we received a message stating end of offset. At gluvr intersection; we received a route discontinuity and the aircraft went into the roll mode I believe. My first officer immediately re-entered the arrival with the next intersection; crsty. By that time; ATC gave us a 090 heading and mentioned that we were just south of the course. We informed him we were turning back and we were given direct to villi intersection and resume the arrival. Rest of flight proceeded normally.I failed to enter an end of offset waypoint which led to the aircraft deviating from the assigned route. I've used the offset function many times in the past and honestly don't remember having this ever happening. My first officer was fairly new and had never used the offset function; so he was relying on my entries to be accurate; which they were not. I'll be sure to take my time and understand what I am selecting and executing the next time when making entries into the FMC.

Original NASA ASRS Text

Title: B737-700 Captain reported a track deviation occurred during a route offset to avoid wake turbulence.

Narrative: I was Pilot Flying on flight to HOU. We were cleared to descend via the KIDDZ 3 Arrival; landing Runway 31. I believe around the KIDDZ intersection; we started to encounter mild wake turbulence from Company aircraft approximately 10 miles in front of us. I went into the FMC and programmed a .1L offset to stay out of his wake. I did not enter a start or end waypoint for the offset. Sometime later; we received a message stating end of offset. At GLUVR intersection; we received a route discontinuity and the aircraft went into the roll mode I believe. My First Officer immediately re-entered the arrival with the next intersection; CRSTY. By that time; ATC gave us a 090 heading and mentioned that we were just south of the course. We informed him we were turning back and we were given direct to VILLI intersection and resume the arrival. Rest of flight proceeded normally.I failed to enter an end of offset waypoint which led to the aircraft deviating from the assigned route. I've used the offset function many times in the past and honestly don't remember having this ever happening. My First Officer was fairly new and had never used the offset function; so he was relying on my entries to be accurate; which they were not. I'll be sure to take my time and understand what I am selecting and executing the next time when making entries into the FMC.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1603281
Time
Date	201812
Local Time Of Day	0601-1200
Place
Locale Reference	HOU.Airport
State Reference	TX
Environment
Light	Daylight
Aircraft 1
Make Model Name	B737-700
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR KIDDZ3
Flight Plan	IFR
Aircraft 2
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Flight Phase	Descent
Route In Use	STAR KIDDZ3
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 421
Events
Anomaly	Deviation - Procedural Clearance Deviation - Track / Heading All Types Inflight Event / Encounter Wake Vortex Encounter