Acquisition - Supplemental Pro Forma Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Earnings per share
Restructuring charges	$ 1,642	$ 0	$ 1,642	$ 0
Branch optimization plan, restructuring charges, earnings per share, diluted	$ 0.05		$ 0.05
Valley Green Bank [Member]
Business Acquisition [Line Items]
Net interest income	$ 23,380	22,733	$ 46,684	45,645
Noninterest income	13,351	12,068	26,782	24,365
Noninterest expense	26,832	24,164	54,243	47,561
Net income	$ 6,466	$ 6,485	$ 12,582	$ 13,903
Earnings per share
Basic (in dollars per share)	$ 0.33	$ 0.32	$ 0.64	$ 0.69
Diluted (in dollars per share)	$ 0.33	$ 0.32	$ 0.63	$ 0.69
Integration and acquisition-related costs, gross	$ 151		$ 2,000
Integration and acquisition-related costs, net of tax	$ 98		$ 1,300
Integration and acquisition-related costs, earnings per share, diluted	$ 0		$ 0.07