Acquisition - Supplemental Pro Forma Financial Information (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings per share
Restructuring charges	$ 1,642	$ 0	$ 534
Branch optimization plan, restructuring charges, net of tax	$ 1,100
Branch optimization plan, restructuring charges, earnings per share, diluted	$ 0.05
Valley Green Bank [Member]
Business Acquisition [Line Items]
Net interest income	$ 93,394	92,240
Noninterest income	52,949	49,325
Noninterest expense	105,515	98,729
Net income	$ 27,268	$ 27,468
Earnings per share
Basic (in dollars per share)	$ 1.39	$ 1.37
Diluted (in dollars per share)	$ 1.39	$ 1.37
Integration and acquisition-related costs, gross	$ 2,000
Integration and acquisition-related costs, net of tax	$ 1,300
Integration and acquisition-related costs, earnings per share, diluted	$ 0.07
Fox Chase Bank [Member]
Earnings per share
Integration and acquisition-related costs, gross	$ 540
Integration and acquisition-related costs, net of tax	$ 493
Integration and acquisition-related costs, earnings per share, diluted	$ 0.03