Fair Value (Details 4) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Carrying amount and estimated fair value of financial instruments
Fair value	$ 10,399	$ 8,600
Securities available-for-sale	835,424	853,725
Restricted Investments	10,379	10,359
Accrued interest receivable	13,364	12,311
Deposits	(2,453,411)	(2,428,526)
Fair Value, Inputs, Level 1 [Member]
Carrying amount and estimated fair value of financial instruments
Cash and Cash Equivalents, Fair Value Disclosure	18,709	21,047
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure		0
Securities available-for-sale	0	0
Loans Receivable, Fair Value Disclosure	0	0
Accrued interest receivable	0	0
Deposits	0	0
Short-term borrowings	0	0
Federal Home Loan Bank advances	0	0
Accrued interest payable	0	0
Fair Value, Inputs, Level 2 [Member]
Carrying amount and estimated fair value of financial instruments
Cash and Cash Equivalents, Fair Value Disclosure	42,294	53,965
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure		6,952
Securities available-for-sale	818,052	837,147
Loans Receivable, Fair Value Disclosure	0	0
Accrued interest receivable	3,992	3,340
Deposits	(2,453,096)	(2,414,555)
Short-term borrowings	(23,514)	(80,989)
Federal Home Loan Bank advances	0	(137)
Accrued interest payable	(354)	(363)
Fair Value, Inputs, Level 3 [Member]
Carrying amount and estimated fair value of financial instruments
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure		0
Securities available-for-sale	17,372	16,578
Loans Receivable, Fair Value Disclosure	1,862,884	1,854,046
Accrued interest receivable	9,372	8,971
Deposits	0	0
Short-term borrowings	0	0
Federal Home Loan Bank advances	0	0
Accrued interest payable	0	0
Reported Value Measurement [Member]
Carrying amount and estimated fair value of financial instruments
Cash and Cash Equivalents, Fair Value Disclosure	61,003	75,012
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure		6,952
Securities available-for-sale	835,424	853,725
Restricted Investments	10,379	10,359
Loans Receivable, Fair Value Disclosure	1,846,762	1,820,407
Accrued interest receivable	13,364	12,311
Deposits	(2,453,411)	(2,428,526)
Short-term borrowings	(23,514)	(80,989)
Federal Home Loan Bank advances	0	(132)
Accrued interest payable	(354)	(363)
Estimate of Fair Value Measurement [Member]
Carrying amount and estimated fair value of financial instruments
Cash and Cash Equivalents, Fair Value Disclosure	61,003	75,012
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure		6,952
Securities available-for-sale	835,424	853,725
Loans Receivable, Fair Value Disclosure	1,862,884	1,854,046
Accrued interest receivable	13,364	12,311
Deposits	(2,453,096)	(2,414,555)
Short-term borrowings	(23,514)	(80,989)
Federal Home Loan Bank advances	0	(137)
Accrued interest payable	$ (354)	$ (363)