Acquisition - Narrative (Details) $ / shares in Units, $ in Thousands		9 Months Ended
	Jan. 01, 2015 USD ($) community Office $ / shares shares	Sep. 30, 2015 USD ($) $ / shares	Dec. 31, 2014 USD ($) $ / shares
Business Acquisition [Line Items]
Common stock, par value | $ / shares	$ 5	$ 5	$ 5
Deposits		$ 2,372,865	$ 1,861,341
Interest component of expected cash flows (accretable difference)		185	$ 0
Valley Green Bank [Member]
Business Acquisition [Line Items]
Number of banking office operates in greater Philadelphia marketplace | community	3
Number of loan production offices in Philadelphia marketplace | Office	2
Merger agreement aggregate value	$ 77,000
Outstanding stock options prior to exchange | shares	122,377
Cash and related payroll taxes exchanged for employee stock options	$ 2,200
Purchase price assigned to cash in lieu of fractional shares	3
Deposits	385,900
Fair value of loans	379,200
Fair value premium	4,400
Fair value discount	$ 5,500
Fair value adjustment, period of amortization	10 years
Acquired impaired loans	$ 1,700
Contractual cash flows not expected to be collected (nonaccretable difference)	5,344
Interest component of expected cash flows (accretable difference)	305
Customer related intangibles	$ 1,520
Useful life of intangible asset	10 years
Fair value premium	$ 686
Integration and acquisition-related costs, gross		$ 2,000