Unaudited Condensed Consolidated Statements of Changes in Shareholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2016	7,509
Beginning balance at Dec. 31, 2016	$ 939	$ 51,885	$ 134,650	$ (3,408)	$ 184,066
Net income			7,811		7,811
Other comprehensive loss				2,352	2,352
Cash dividends declared – common			(1,502)		(1,502)
Shares issued under director compensation plan (in shares)	1
Shares issued under director compensation plan		46			46
Shares issued pursuant to employee stock purchase plan (in shares)	3
Shares issued pursuant to employee stock purchase plan		87			87
Expense related to employee stock purchase plan		16			16
Balance (in shares) at Jun. 30, 2017	7,513
Ending balance at Jun. 30, 2017	$ 939	52,034	140,959	(1,056)	192,876
Beginning balance at Mar. 31, 2017				(2,395)
Net income					4,482
Other comprehensive loss				1,339	1,339
Balance (in shares) at Jun. 30, 2017	7,513
Ending balance at Jun. 30, 2017	$ 939	52,034	140,959	(1,056)	192,876
Adoption of Accounting Standards Update 2016-01
Balance (in shares) at Dec. 31, 2017	7,517
Beginning balance at Dec. 31, 2017	$ 940	52,201	143,778	(3,566)	193,353
Net income			11,488		11,488
Other comprehensive loss				(5,216)	(5,216)
Cash dividends declared – common			(1,880)		(1,880)
Shares issued under director compensation plan (in shares)	1
Shares issued under director compensation plan		36			36
Shares issued pursuant to employee stock purchase plan (in shares)	3
Shares issued pursuant to employee stock purchase plan		95			95
Expense related to employee stock purchase plan		16			16
Balance (in shares) at Jun. 30, 2018	7,521
Ending balance at Jun. 30, 2018	$ 940	52,348	153,442	(8,838)	197,892
Beginning balance at Mar. 31, 2018				(7,725)
Net income					5,847
Other comprehensive loss				(1,113)	(1,113)
Balance (in shares) at Jun. 30, 2018	7,521
Ending balance at Jun. 30, 2018	$ 940	52,348	153,442	(8,838)	197,892
Adoption of Accounting Standards Update 2016-01			$ 56	$ (56)