Income Taxes (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Components of income taxes
Current									$ 1,926,000	$ 2,194,000	$ 7,353,000
Deferred									8,571,000	12,776,000	2,111,000
Total income tax (benefit) expense	2,556,000	2,331,000	1,877,000	3,733,000	2,753,000	4,151,000	3,955,000	4,111,000	10,497,000	14,970,000	9,464,000
Reconciliation of federal and state income taxes at statutory rates to the income taxes included in the statements of operations
Income tax (benefit) at statutory rate (as a percent)									35.00%	35.00%	35.00%
Tax-exempt interest, net (as a percent)									(4.50%)	(2.60%)	(3.70%)
State income taxes, net (as a percent)									3.50%	2.10%	2.00%
Income on bank owned life insurance (as a percent)									(1.80%)	(1.00%)	(1.90%)
ESOP dividends (as a percent)									(0.20%)	(0.10%)	(0.20%)
Other, net (as a percent)									(0.10%)		(2.30%)
Total (as a percent)									31.90%	33.40%	28.90%
Deferred tax assets:
Allowance for loan losses	19,597,000				23,881,000				19,597,000	23,881,000
Stock-based compensation	1,183,000				795,000				1,183,000	795,000
Loan adjustments	396,000				131,000				396,000	131,000
Deferred compensation	1,993,000				1,956,000				1,993,000	1,956,000
Accrued vacation	576,000				511,000				576,000	511,000
Employee costs	616,000				385,000				616,000	385,000
Other	1,423,000				1,448,000				1,423,000	1,448,000
Total	25,784,000				29,107,000				25,784,000	29,107,000
Investment securities:
Unrealized gains on securities available for sale	(9,479,000)				(9,187,000)				(9,479,000)	(9,187,000)
Other	(2,273,000)				(2,004,000)				(2,273,000)	(2,004,000)
Basis in premises and equipment	(2,215,000)				(3,170,000)				(2,215,000)	(3,170,000)
Mortgage servicing assets	(2,159,000)				(2,232,000)				(2,159,000)	(2,232,000)
Basis in core deposit and customer intangibles	(5,185,000)				(6,538,000)				(5,185,000)	(6,538,000)
Deferred loan origination costs	(303,000)				(285,000)				(303,000)	(285,000)
Deferred tax liabilities	(21,614,000)				(23,416,000)				(21,614,000)	(23,416,000)
Net operating loss carryforward, net of valuation allowance	35,203,000				42,545,000				35,203,000	42,545,000
Net deferred tax asset	39,373,000				48,236,000				39,373,000	48,236,000
Federal and Illinois
Operating loss carryforwards
Net operating loss carryforwards	35,200,000				42,500,000				35,200,000	42,500,000
Indiana and Florida
Operating loss carryforwards
Net operating loss carryforwards	1,800,000								1,800,000
Valuation allowance	$ 1,800,000								$ 1,800,000