Loans and Allowance - Narrative (Detail) (USD $)					12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Feb. 10, 2012 SCB Bank	Nov. 12, 2013 Merger with CFS Bancorp, Inc. (Citizens)	Dec. 31, 2013 Commercial and farmland	Dec. 31, 2013 Residential
Accounts, Notes, Loans and Financing Receivable [Line Items]
Residential real estate loans held for sale	$ 5,331,000	$ 22,300,000
Loan Acquired during acquisition			113,000,000	639,600,000
Fair Value Discount			$ 19,200,000	$ 36,500,000
Percentage of troubled debt restructured loans					75.00%	17.00%