Subsequent Events	12 Months Ended
Dec. 31, 2013
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS Subsequent events have been evaluated for potential recognition and disclosure through the date financial statements were filed with the Securities and Exchange Commission. On January 23, 2014, the Company declared a quarterly dividend to common shareholders of $0.16 per share, to be paid on February 14, 2014 to shareholders of record as of February 4, 2014 . On January 24, 2014, the Company filed a Registration Statement on Form S-8 to register an additional 1,500,000 share of Class A common stock to be issued pursuant to the Company's 2006 Equity Compensation Plan, as amended and restated. On February 10, 2014, the Company entered into an agreement and plan of merger to acquire all of the outstanding stock of Mountain West Financial Corp ("Mountain West"), a Montana-based bank holding company that operates one wholly-owned subsidiary bank, Mountain West Bank, NA, with branches located in five of the Company's current market areas in Montana. Under the terms of the agreement and plan of merger, each outstanding share of Mountain West common stock will be canceled and converted into the right to receive 0.2552 shares of the Company's Class A common stock plus $7.125 in cash, or, if a Mountain West stockholder properly elects and subject to the limitations contained within the agreement and plan of merger, an amount in all cash or all stock intended to be substantially equal in value to the above described combination of stock and cash merger consideration. The value received by Mountain West stockholders in the aggregate and on a per share of Mountain West common stock basis will fluctuate prior to the completion of the merger based on the prevailing market price of the Company's Class A common stock at the time the transaction is consummated. The merger is expected to close in mid-2014, subject to several conditions, including, among other things, receipt of applicable regulatory approval and approval by the stockholders of Mountain West. The Company anticipates that within six months following the consummation of the merger, Mountain West Bank, NA will be merged with and into FIB. No other events requiring recognition or disclosure were identified.

SUBSEQUENT EVENTS

Subsequent events have been evaluated for potential recognition and disclosure through the date financial statements were filed with the Securities and Exchange Commission. On January 23, 2014, the Company declared a quarterly dividend to common shareholders of $0.16 per share, to be paid on February 14, 2014 to shareholders of record as of February 4, 2014 .

On January 24, 2014, the Company filed a Registration Statement on Form S-8 to register an additional 1,500,000 share of Class A common stock to be issued pursuant to the Company's 2006 Equity Compensation Plan, as amended and restated.

On February 10, 2014, the Company entered into an agreement and plan of merger to acquire all of the outstanding stock of Mountain West Financial Corp ("Mountain West"), a Montana-based bank holding company that operates one wholly-owned subsidiary bank, Mountain West Bank, NA, with branches located in five of the Company's current market areas in Montana.

Under the terms of the agreement and plan of merger, each outstanding share of Mountain West common stock will be canceled and converted into the right to receive 0.2552 shares of the Company's Class A common stock plus $7.125 in cash, or, if a Mountain West stockholder properly elects and subject to the limitations contained within the agreement and plan of merger, an amount in all cash or all stock intended to be substantially equal in value to the above described combination of stock and cash merger consideration. The value received by Mountain West stockholders in the aggregate and on a per share of Mountain West common stock basis will fluctuate prior to the completion of the merger based on the prevailing market price of the Company's Class A common stock at the time the transaction is consummated.

The merger is expected to close in mid-2014, subject to several conditions, including, among other things, receipt of applicable regulatory approval and approval by the stockholders of Mountain West. The Company anticipates that within six months following the consummation of the merger, Mountain West Bank, NA will be merged with and into FIB.

No other events requiring recognition or disclosure were identified.