Securities - Additional Information (Details 4) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Securities Pledged
Securities pledged to various federal reserve districts, amortized cost	$ 103,400	$ 55,000
Securities pledged to various federal reserve districts, fair value	103,600	54,800
Repurchase Agreements [Member]
Securities Pledged
Amortized cost of securities pledged	15,500	17,700
Securities pledged and available to be sold under repurchase agreements, fair value	15,600	17,900
Derivative [Member]
Securities Pledged
Amortized cost of securities pledged	515	669
Securities pledged and available to be sold under repurchase agreements, fair value	$ 540	$ 701