Merger and Acquisition Activity (Details Textual) (USD $) In Thousands, unless otherwise specified	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Apr. 11, 2014	Jun. 14, 2012
Business Acquisition [Line Items]
Purchase premium	$ 0	$ 0	$ 851
Total fair value of assets acquired					107,364
Northwoods National Bank [Member]
Business Acquisition [Line Items]
Core deposit intangible, Amortization period				5 years
Purchase premium				654
Incurred and expensed non-recurring				371
Data Processing Conversion Costs				224
Total fair value of assets acquired				40,818
Accounting date					Jun. 01, 2012
Percentage of tangible net book value					100.00%
Marathon State Bank book equity ratio as percent of assets prior to acquisition					6.00%
Credit Markdown on Acquired Loan Portfolio					490
Credit Markdown on Acquired Loan Portfolio, percentage					2.05%
Purchased Impaired Loan Balance					310
Write-down, impaired loans					21
Marathon State Bank [Member]
Business Acquisition [Line Items]
Total fair value of assets acquired					$ 107,000