Columbia Banking System Inc., the Tacoma, Wash.-based parent of Columbia State Bank, has signed an agreement to merge into its operations Intermountain Community Bancorp, the Sandpoint-based company that operates Intermountain Community Bank and Panhandle State Bank.

The transaction is valued at about $121.5 million and is expected to be completed during this year’s fourth quarter. When completed, Columbia will have $8.2 billion in assets and more than 150 branches throughout Washington, Oregon, and Idaho.

The acquisition will give Columbia its first physical presence in Idaho.

Melanie J. Dressel, Columbia’s president and CEO, said in a press release, “We have stated for many years that it has long been our strategy to become the premier Pacific Northwest community bank. We have always felt that Idaho was an important part of that strategy.”

Columbia first entered the Spokane market in 2011 when it acquired eight former Bank of Whitman branches after the Federal Deposit Insurance Corp. shut down that Colfax, Wash.-based bank.

Intermountain operates as four separate divisions with 19 banking locations in three states. Intermountain Community Bank Washington, a division of IMCB banking subsidiary Panhandle State Bank, operates branches in downtown Spokane and Spokane Valley.

Separately, Intermountain Community Bancorp reported second-quarter net income of $1.3 million, or 19 cents a diluted share, down from income of $1.5 million, or 23 cents a share, in the year-earlier period. Its net loans declined slightly to $520.3 million as of June 30 from $522.7 million, and its total deposits fell to $693.9 million on June 30 from $699.5 million a year earlier.