Consolidated Statements of Changes in Stockholders' Equity (Unaudited) - 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	22,617
Balance at Dec. 31, 2016	$ 36,250	$ 26,682	$ 252,439	$ (1,499)		$ 313,872
Net income			21,393			21,393
Other comprehensive income, net of tax				890		890
Stock compensation expense		1,342				1,342
Stock issued for share-based awards, net of withholdings to satisfy employee tax obligations upon award (in shares)	50
Stock issued for share-based awards, net of withholdings to satisfy employee tax obligations upon award	$ 164	1,820	(4,146)			(2,162)
Cash dividends			(8,835)			(8,835)
Shares cancelled (in shares)	(5)
Shares cancelled	$ (14)	(91)	105
Balance (in shares) at Jun. 30, 2017	22,662
Balance at Jun. 30, 2017	$ 36,400	29,753	260,956	(609)		326,500
Balance at Mar. 31, 2017				(725)
Net income						10,602
Other comprehensive income, net of tax				116		116
Balance (in shares) at Jun. 30, 2017	22,662
Balance at Jun. 30, 2017	$ 36,400	29,753	260,956	(609)		326,500
Balance (in shares) at Dec. 31, 2017	22,679
Balance at Dec. 31, 2017	$ 36,457	31,924	267,193	(1,930)	[1]	333,644
Net income			26,983			26,983
Other comprehensive income, net of tax				(4,608)		(4,608)
Stock compensation expense		2,035				2,035
Stock issued for share-based awards, net of withholdings to satisfy employee tax obligations upon award (in shares)	69
Stock issued for share-based awards, net of withholdings to satisfy employee tax obligations upon award	$ 231	823	(3,140)			(2,086)
Cash dividends			(10,453)			(10,453)
Shares cancelled (in shares)	(2)
Shares cancelled	$ (8)	(67)	75
Balance (in shares) at Jun. 30, 2018	22,746
Balance at Jun. 30, 2018	$ 36,680	34,715	281,164	(7,044)		345,515
Balance at Mar. 31, 2018				(5,844)
Net income						13,579
Other comprehensive income, net of tax				(1,200)		(1,200)
Balance (in shares) at Jun. 30, 2018	22,746
Balance at Jun. 30, 2018	$ 36,680	34,715	281,164	(7,044)		345,515
Reclassification adjustment under Accounting Standard Update 2018-02			$ 506	$ (506)

[1] December 31, 2017 AOCI component balances reflect a correction of incorrectly reported year-end balances in Note 12 of the 2017 Form 10-K, which were presented as $(2,278), $234, and $(392) for securities available-for-sale, cash flow hedges, and minimum pension liability, respectively.