To come full circle could work. Here are several definitions and examples of the phrase:
To return to the same situation or attitude you originally had. I left publishing, tried teaching, and now I've come full circle back to publishing.
When something “comes full circle,” it completes a cycle, returns to its beginnings: The novelist's vision of human life has come full circle—from optimism to pessimism and back to optimism again. 
In the comments below, an idiom describing "returning to a starting point after going around in a full circle[,] especially in the context of unsuccessfully trying to find one's way in a maze" was requested.
I would suggest Going around in circles or Walking in circles. Examples:
To move over and over on a circular path. The model plane went around in circles until it ran out of fuel. The oxen went around in circles, pulling along a beam that was connected to the millstone.
To act in a confused and disoriented manner. I've been going around in circles all day. The children have been going around in circles, waiting for you to arrive.
To keep going over the same ideas or repeating the same actions, often resulting in confusion, without reaching a satisfactory decision or conclusion. We're just going round in circles discussing the problem. We need to consult someone else to get a new point of view. Fred's trying to find out what's happened but he's going round in circles. No one will tell him anything useful.
This expression is frequently used in the context of being lost. Upon realizing that one has returned to a location one has already visited, one might remark, "it looks like I've been walking in circles".
1 The Cambridge Dictionary of American Idioms © 2002
2 The American Heritage New Dictionary of Cultural Literacy, Third Edition © 2005
2 McGraw-Hill Dictionary of American Idioms and Phrasal Verbs © 2005