CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands		Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning Balance (in shares) at Dec. 31, 2017			15,524,704
Beginning Balance at Dec. 31, 2017		$ 403,413	$ 156,904	$ 266,723	$ (20,214)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		12,820		12,820
Other comprehensive loss, net of tax(2)	[1]	(9,907)			(9,907)
Stock-based compensation expense		431	$ 431
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings and tax benefit (shares)			41,164
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings		(475)	$ (475)
Cash dividends declared ($0.46 and $0.55 per share		(3,900)		(3,900)
Ending Balance (in shares) at Mar. 31, 2018			15,565,868
Ending Balance at Mar. 31, 2018		403,047	$ 156,860	275,841	(29,654)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative-effect adjustment upon adoption of ASU 2016-02(3) | ASU 2016-01	[2]			198	(198)
Cumulative-effect adjustment upon adoption of ASU 2016-02(3) | Adjustments for New Accounting Pronouncement [Member]	[1]	665			665
Stock Repurchased During Period, Value		2,306	$ (2,306)	0	0
Beginning Balance (in shares) at Dec. 31, 2018			15,591,914
Beginning Balance at Dec. 31, 2018		435,825	$ 158,215	302,030	(24,420)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income		14,273		14,273
Other comprehensive loss, net of tax(2)		10,116			10,116
Stock-based compensation expense		458	$ 458
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings and tax benefit (shares)			24,208
Exercise of stock options and issuance of vested share awards, net of repurchase for tax withholdings		(215)	$ (215)
Cash dividends declared ($0.46 and $0.55 per share		(4,687)		(4,687)
Ending Balance (in shares) at Mar. 31, 2019			15,560,565.000
Ending Balance at Mar. 31, 2019		453,718	$ 156,152	311,870	(14,304)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock Repurchased During Period, Shares			(55,557)
Cumulative-effect adjustment upon adoption of ASU 2016-02(3)					$ 0
Cumulative-effect adjustment upon adoption of ASU 2016-02(3) | ASU 2016-02	[3]	$ 254		$ 254

[1] (2) Effective January 1, 2018, the Company adopted ASU 2017-12, Derivatives and Hedging. In conjunction with the adoption, the Company made the transition election to reclassify qualifying securities designated as held-to-maturity to available-for-sale.

[2] (1)Effective January 1, 2018, the Company adopted ASU 2016-01, Income Statement - Financial Instruments. As a result of the adoption, the Company reclassified its unrealized gain on equity investments from accumulated other comprehensive loss to retained earnings.

[3] (3) Effective January 1, 2019, the Company adopted ASU 2016-02, Leases, on a modified-retrospective basis. Refer to Note 2 for further details.