BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Textual) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Noncontrolling Interest [Line Items]
Interest-bearing deposits in banks and other financial institutions	$ 404,005,000	$ 371,318,000
Required daily cash and cash equivalents reserve balance	14,600,000	13,100,000
Federal Reserve stock, investment requirement as a percent of First Bank capital stock and capital surplus	6.00%
Federal Home Loan Bank of Des Moines [Member]
Noncontrolling Interest [Line Items]
Federal Home Loan Bank stock, investment requirement as a percent of First Bank total Assets	0.12%
Federal Home Loan Bank stock, investment requirement, maximum amount	10,000,000
Federal Home Loan Bank stock, investment requirement, maximum, percent of advances	4.45%
Federal Home Loan Bank stock	7,900,000	8,800,000
Federal Reserve Bank of St. Louis [Member]
Noncontrolling Interest [Line Items]
Federal Reserve Bank stock	$ 19,400,000	$ 18,300,000
First Capital America, Inc.
Noncontrolling Interest [Line Items]
Noncontrolling interest, ownership percentage by parent	46.77%
First Bank
Noncontrolling Interest [Line Items]
Noncontrolling interest, ownership percentage by parent	53.23%
Buildings and improvements | Minimum
Noncontrolling Interest [Line Items]
Property, plant and equipment, useful life	5 years
Buildings and improvements | Maximum
Noncontrolling Interest [Line Items]
Property, plant and equipment, useful life	40 years
Equipment | Minimum
Noncontrolling Interest [Line Items]
Property, plant and equipment, useful life	3 years
Equipment | Maximum
Noncontrolling Interest [Line Items]
Property, plant and equipment, useful life	7 years