Loans Held for Sale and Loan Servicing Narrative Data (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Servicing Assets at Fair Value [Line Items]
Unpaid principal balance of loans serviced for others	$ 422,300,000	$ 365,400,000
Net gains on sales of loans held for sale	2,871,000	2,097,000	$ 2,305,000
Loan servicing rights, unamortized balance	1,500,000	1,400,000
Loan servicing rights, valuation allowance	0	0
Loan servicing rights, capitalized	839,000	571,000	737,000
Loan servicing rights, Amortization	670,000	528,000	507,000
Residential Real Estate [Member]
Servicing Assets at Fair Value [Line Items]
Loans sold during the year	131,700,000	94,900,000	123,100,000
Net gains on sales of loans held for sale	2,900,000	2,100,000	2,300,000
Commercial [Member]
Servicing Assets at Fair Value [Line Items]
Loans sold during the year	0	0	$ 0
Credit Enhancement Obligation [Member]
Servicing Assets at Fair Value [Line Items]
Contractual risk sharing commitments, maximum liability	$ 595,000	$ 523,000