BILLINGS, Mont.--(BUSINESS WIRE)--First Interstate BancSystem, Inc. (NASDAQ:FIBK) reports second quarter 2015 net income of $22.2 million, or $0.49 per share. This compares to net income of $21.0 million, or $0.46 per share, during first quarter 2015, and $21.1 million, or $0.47 per share, during second quarter 2014. SECOND QUARTER HIGHLIGHTS Pre-tax, pre-provision income of $35.1 million, a 7.9% increase from the prior quarter and a 15.5% increase from the same period in the prior year. Organi