Acquisition of MainStreet - Narrative (Details) - USD ($)		6 Months Ended
	Jan. 01, 2015	Jun. 30, 2015	Dec. 31, 2011
Business Combinations [Abstract]
Shares received by acquiree entity in exchange of acquirer entity's common stock (in dollars per share)	$ 3.46
Shares received by acquiree entity in exchange of acquirer entity's common stock (in shares)	0.482
Shares exchange ratio on acquisition	64.30%
Cash dividends received for purchase of acquisition	$ 6,000,000
Amount of loan taken to fund merger	$ 0
Number of shares granted in conjunction with the acquisition	43,086	43,086
Amount of acquired loan portfolio	$ 122,300,000
Acquired loan portfolio, at a fair value discount	7,400,000
Estimated fair value of performing portion of the portfolio	105,800,000
Deferred income taxes	2,683,000
Premises and equipment	1,475,000	$ 1,475,000
Valuation adjustment due to acquisition	$ 290,000
Period valuation adjustment recognized over	12 months
Core deposits intangibles recognized due to the acquisition	$ 1,839,000
Amortization period of core deposit	10 years
Merger and acquisition expenses			$ 1,861,000