Basis of Presentation

6 Months Ended

Jun. 30, 2011

Basis of Presentation [Abstract]

Basis of Presentation

(1) Basis of Presentation

In the opinion of management, the accompanying unaudited consolidated financial statements of First Interstate BancSystem, Inc. and subsidiaries (the “Company”) contain all adjustments (all of which are of a normal recurring nature) necessary to present fairly the financial position of the Company at June 30, 2011 and December 31, 2010, the results of operations for each of the three and six month periods ended June 30, 2011 and 2010, and cash flows for the six months ended June 30, 2011 and 2010, in conformity with U.S. generally accepted accounting principles. The balance sheet information at December 31, 2010 is derived from audited consolidated financial statements. Certain reclassifications, none of which were material, have been made to conform prior year financial statements to the June 30, 2011 presentation. These reclassifications did not change previously reported net income or stockholders’ equity.

These unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and related notes included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2010. Operating results for the three and six months ended June 30, 2011 are not necessarily indicative of the results that may be expected for the year ending December 31, 2011.