Here I go, raining on the Costco parade. I found this list of store openings that goes well into 2013, with no mention of Idaho Falls. The source is a blog called Addicted to Costco. Here is the link:
http://addictedtocostco.com/costco-locations/comment-page-55/#comment-131679
You might notice a lot of commenters from all over the country saying the same thing people are saying here: "We want Costco!" Take a number, I guess.
New Locations: (Updated 2012.09.11)
TAOYUAN, TAIWAN August 30, 2012
ULSAN, KOREA August 31, 2012
WHEATON, MD October 18, 2012
WEST EDMONTON, ALBERTA, CANADA October 19, 2012
WEST FARGO, ND October 23, 2012
BAXTER, MN October 24, 2012
SPANISH FORK, UT October 25, 2012
FARRAGUT, TN November 9, 2012
CONCORDVILLE, PA November 10, 2012
EAST PEORIA, IL November 14, 2012
SUN PRAIRIE, WI November 15, 2012
ROCHESTER, MN November 16, 2012
DRUMMONDVILLE, QUEBEC, CANADA November 27, 2012
OSHAWA, ONTARIO, CANADA November 28, 2012
WASHINGTON, D.C. November 29, 2012
Tentative opening dates:
THURMASTON, LEICESTER, UNITED KINGDOM End 2012/Early 2013
GWANGMYEONG STATION, SEOUL KOREA January 2013
HIROSHIMA, JAPAN March 2013
UKIAH, CA Late 2012/Early 2013
ALEXANDRIA, VA Early 2013
BRISBANE, AUSTRALIA Spring 2013
SOUTHAMPTON, UK Spring 2013
NEW ORLEANS, LA Summer 2013
RINGWOOD, VICTORIA, AUSTRALIA Summer 2013
LEXINGTON, KENTUCKY Mid to Late 2013
FORT WAYNE, INDIANA Mid to Late 2013
ADELAIDE, AUSTRALIA Mid to Late 2013
GUELPH, ONTARIO, CANADA Fall 2013
YORKTOWN, NY Fall 2013
BATON ROUGE, LA 2013
SIOUX FALLS, SD 2013
CEDAR PARK, TX Late 2013/Early 2014
ST. ALBERT, ALBERTA, CANADA 2013
NAPA, CALIFORNIA Late 2013
WICHITA, KANSAS Late 2013