Fair Value (Details 4) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Carrying amount and estimated fair value of financial instruments
Fair value	$ 13,578	$ 10,082
Securities available-for-sale	805,558	814,931
Restricted Investments	10,390	10,379
Accrued interest receivable	12,983	12,913
Deposits	(2,457,189)	(2,458,653)
Fair Value, Inputs, Level 1 [Member]
Carrying amount and estimated fair value of financial instruments
Cash and Cash Equivalents, Fair Value Disclosure	19,278	20,682
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure	0	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	21,878	53,425
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure	1,500	0
Securities available-for-sale	786,893	796,646
Loans Receivable, Fair Value Disclosure	0	0
Accrued interest receivable	3,905	3,596
Deposits	(2,444,875)	(2,456,900)
Short-term borrowings	(29,078)	(57,686)
Federal Home Loan Bank advances	0	0
Accrued interest payable	(367)	(372)
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	0
Securities available-for-sale	18,665	18,285
Loans Receivable, Fair Value Disclosure	1,832,520	1,878,166
Accrued interest receivable	9,078	9,317
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	41,156	74,107
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure	1,500	0
Securities available-for-sale	805,558	814,931
Restricted Investments	10,390	10,379
Loans Receivable, Fair Value Disclosure	1,887,203	1,886,852
Accrued interest receivable	12,983	12,913
Deposits	(2,457,189)	(2,458,653)
Short-term borrowings	(29,078)	(57,686)
Federal Home Loan Bank advances	0	0
Accrued interest payable	(367)	(372)
Estimate of Fair Value Measurement [Member]
Carrying amount and estimated fair value of financial instruments
Cash and Cash Equivalents, Fair Value Disclosure	41,156	74,107
Federal Funds Sold and Securities Borrowed or Purchased under Agreements to Resell, Fair Value Disclosure	1,500	0
Securities available-for-sale	805,558	814,931
Loans Receivable, Fair Value Disclosure	1,832,520	1,878,166
Accrued interest receivable	12,983	12,913
Deposits	(2,444,875)	(2,456,900)
Short-term borrowings	(29,078)	(57,686)
Federal Home Loan Bank advances	0	0
Accrued interest payable	$ (367)	$ (372)