The SEC XBRL previewer absolutely rocks, and you can try it for yourself. You don't need to be a public company or have a CIK number. Here is how to do it.
First, grab this file, you can use it as a first test: 00000000001.zip (You can just put your mouse over the ZIP file link, right click and select "Save target as..." Note that I grabbed this set of files from the SEC EDGAR system and I have run it and I know it works. This is the filing submitted by "The NASDAQ OMX Group, Inc." This is public information. Or, you can create your own test submission and view that.)
Second, go to this web page: Privately Preview your Interactive Data Submissions
Third, you can enter any CIK number you want. Fill in the information on the left side of the form. Put in the CIK number you want, upload the file from above (or a file you created), enter the security code, and then press the "Submit" button.
You will be given a confirmation code.
Fourth, wait about 15 minutes. Then, on the RIGHT side of the form; enter the same CIK number you used to submit the filing and then enter that confirmation code you received. Put in the security code again. Press the "Submit" button on the right side.
You can view the different sections of the submission by pressing one of the headings you see on the top of the form you will see. You can also download all the information in an Excel spreadsheet.
The rendering is pretty good and I am sure will only get better. The block text is all smashed together, but that will either be improved or the issue will go away when block text can no longer be used.
Nice work SEC!