Shareholders' Equity and Earnings Per Share - Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of factors used in computing basic and diluted earnings (loss) per common share
Net income available to common shareholders	$ 3,975	$ 3,011	$ 4,029	$ 3,690	$ 3,322	$ 3,145	$ 3,100	$ 2,852	$ 14,705	$ 12,419	$ 11,204
Less: undistributed earnings allocated to Series C Preferred Stock	(209)	(111)	(331)	(274)	(349)	(320)	(358)	(315)	(912)	(1,342)	(1,687)
Distributed and undistributed earnings allocated to common shareholders	$ 3,766	$ 2,900	$ 3,698	$ 3,416	$ 2,973	$ 2,825	$ 2,742	$ 2,537	$ 13,793	$ 11,077	$ 9,517
Weighted average common shares outstanding for basic earnings per common share									28,567,213	26,390,615	26,338,161
Dilutive effect of stock options outstanding, using the treasury stock method (in shares)									218,865	135,667	48,291
Shares used in computing diluted earnings per common share									28,786,078	26,526,282	26,386,452
Net income per share - basic(in dollars per share)	$ 0.12	$ 0.10	$ 0.14	$ 0.13	$ 0.11	$ 0.11	$ 0.10	$ 0.10	$ 0.48	$ 0.42	$ 0.36
Net income per share - diluted(in dollars per share)	$ 0.12	$ 0.10	$ 0.14	$ 0.13	$ 0.11	$ 0.11	$ 0.10	$ 0.10	$ 0.48	$ 0.42	$ 0.36