CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Common Stock, Shares Outstanding, Beginning Balance at Dec. 31, 2015		17,020,000
Shareholders' Equity, Beginning Balance at Dec. 31, 2015	$ 375,388	$ 1,064	$ 110,949	$ 273,074	$ (9,699)
Net income	10,935			10,935
Total other comprehensive income (loss), net of tax	464				464
Cash dividends declared	(6,199)			(6,199)
Share-based compensation	592		592
Exercise of stock options, issuance of other compensation-related equity awards and related tax benefit, shares		4,000
Exercise of stock options, issuance of other compensation-related equity awards and related tax benefit, value	100	$ 0	100
Common Stock, Shares Outstanding, Ending Balance at Mar. 31, 2016		17,024,000
Shareholders' Equity, Ending Balance at Mar. 31, 2016	$ 381,280	$ 1,064	111,641	277,810	(9,235)
Common Stock, Shares Outstanding, Beginning Balance at Dec. 31, 2016	17,170,820	17,171,000
Shareholders' Equity, Beginning Balance at Dec. 31, 2016	$ 390,804	$ 1,073	115,123	294,365	(19,757)
Net income	11,782			11,782
Total other comprehensive income (loss), net of tax	712				712
Cash dividends declared	(6,592)			(6,592)
Share-based compensation	607		607
Exercise of stock options and issuance of other compensation-related equity awards, shares		22,000
Exercise of stock options and issuance of other compensation-related equity awards, value	$ 472	$ 2	470
Common Stock, Shares Outstanding, Ending Balance at Mar. 31, 2017	17,193,025	17,193,000
Shareholders' Equity, Ending Balance at Mar. 31, 2017	$ 397,785	$ 1,075	$ 116,200	$ 299,555	$ (19,045)