Loans and Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable Net of Deferred Income, Acquired	$ 356,299			$ 356,299
Measure taken to reduce the risk of difference in actual value and residual value of the leased assets at maturity				The Corporation greatly reduces this risk primarily by using $1.00 buyout leases, in which the entire cost of the leased equipment is included in the contractual payments, leaving no residual payment at the end of the lease term.
Other accruing impaired loans	19,700			$ 19,700		$ 33,800
Specific reserves for other accruing impaired loans	331			$ 331		$ 476
Maximum modification period on short-term basis				up to one year
Restructured loan past due period				less than ninety days past due
Nonaccrual Troubled Debt Restructured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	0	$ 200	$ 0	$ 200	$ 0
Minimum [Member]
Financing Receivable, Recorded Investment [Line Items]
Amount of loan relationship with risk ratings of grade 1-5 reviewed quarterly	2,500			2,500
Amount of loan relationship with risk ratings of grade 1-5 reviewed annually	500			500
Amount of loan relationship due for review after 60 or more past due days	500			$ 500
Aging period due of reviewing loans rated 1 through 6				60 days
Amount of loan relationship with risk ratings of grade six reviewed quarterly	2,000			$ 2,000
Amount of loan relationship with risk ratings of grade six reviewed annually	$ 500			$ 500
Loan-to-value ratio for residential mortgage loans with private mortgage insurance	80.00%			80.00%
Maximum [Member]
Financing Receivable, Recorded Investment [Line Items]
Amount of loan relationship with risk ratings of grade 1-5 reviewed annually	$ 2,500			$ 2,500
Amount of loan relationship due for review after 60 or more past due days	500			500
Amount of loan relationship with risk ratings of grade six reviewed annually	$ 2,000			$ 2,000
Loan-to-value ratio for residential mortgage loans without private mortgage insurance	80.00%			80.00%
Combined loan-to-value ratio for home equity loans without private mortgage insurance	80.00%			80.00%
Combined loan-to-value ratio for home equity loans without private mortgage insurance for corporations strongest profile borrower	85.00%			85.00%
Valley Green Bank [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable Net of Deferred Income, Acquired	$ 1,900			$ 1,900