Mortgage Servicing (Additional Information) (Details) - USD ($)		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Servicing Assets at Fair Value [Line Items]
Servicing Asset at Amortized Cost		$ 1,210,000		$ 2,161,000		$ 493,000	$ 726,000
Servicing Asset at Fair Value, Amount	[2]	$ 1,701,000	[1]	$ 2,947,000	[1]	1,447,000	$ 1,494,000
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Prepayment Speed		14.60%		11.00%
Servicing Assets and Servicing Liabilities at Fair Value, Assumptions Used to Estimate Fair Value, Discount Rate		7.80%		7.50%
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Adverse Change in Prepayment Speed		$ 97,000
Fees and Commissions, Mortgage Banking and Servicing		1,100,000		$ 597,000		484,000
Gain (Loss) on Sale of Mortgage Loans		6,201,000		1,278,000		31,000
Receivables Held-for-sale, Amount		15,100,000		10,800,000
Unrealized Gain (Loss) on Derivatives		(289,000)		133,000
Unrealized gain (loss) on loans held for sale		(422,000)		133,000		0
Mortgage loans serviced during period, value		930,800,000		963,000,000
Advance Payments by Borrowers for Taxes and Insurance		2,000,000		4,900,000
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Prepayment Speed		185,000
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 10 Percent Adverse Change in Discount Rate		57,000
Sensitivity Analysis of Fair Value, Transferor's Interests in Transferred Financial Assets, Impact of 20 Percent Adverse Change in Discount Rate		111,000
Capitalized servicing right fees upon sale(1)	[3]	9,000		294,000		15,000
Maine State Housing Authority [Member]
Servicing Assets at Fair Value [Line Items]
Fees and Commissions, Mortgage Banking and Servicing		1,700,000		1,200,000		1,200,000
Mortgage loans serviced during period, value		619,100,000		612,100,000
Custodial escrow balances		6,300,000		4,300,000
Fixed Rate Residential Mortgage [Member]
Servicing Assets at Fair Value [Line Items]
Mortgage Loans on Real Estate, Cost of Mortgages Sold		232,200,000		61,200,000		799,000
Custodial escrow balances		11,900,000		7,100,000
Accounts Receivable, Net		2,700,000		5,700,000
Allowance for Doubtful Accounts Receivable		$ 829,000		489,000
US Treasury Notes Securities [Member]
Servicing Assets at Fair Value [Line Items]
Term to maturity (years)		10 years
SBM Financial, Inc. [Member]
Servicing Assets at Fair Value [Line Items]
Capitalized servicing right fees upon sale(1)		$ 0		$ 1,608,000		$ 0

[1] Reported fair value represents all MSRs currently being serviced by the Company at December 31, 2015.

[2] Reported fair value represents all MSRs currently being serviced by the Company.

[3] Reported within mortgage banking income, net on the Company's consolidated statements of income.