CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment [Member]	Common Stock [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]	Retained Earnings [Member] Cumulative Effect, Period of Adoption, Adjustment [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
BALANCE at Dec. 31, 2018	$ 182,498		$ 327	$ 181,815	$ 105,212			$ (431)
BALANCE, Shares at Dec. 31, 2018			32,723,972
BALANCE, Treasury Stock, Value at Dec. 31, 2018							$ (104,425)
BALANCE, Treasury Stock, Shares at Dec. 31, 2018							(2,808,361)
Net income	48,965				48,965
Issuance of common stock awards to employees, value			$ 2	(2)
Issuance of common stock awards to employees, shares			139,862
Surrender of common stock awards, value	(2,331)						$ (2,331)
Surrender of common stock awards, shares							(46,394)
Share-based compensation expense	6,144			6,144
Share-based compensation issued to directors, value	259			259
Share-based compensation issued to directors, shares			7,670
Other comprehensive income (loss), net of tax	(8,021)							(8,021)
BALANCE at Sep. 30, 2019	227,514		$ 329	188,216	154,177			(8,452)
BALANCE, Shares at Sep. 30, 2019			32,871,504
BALANCE, Treasury Stock, Value at Sep. 30, 2019							$ (106,756)
BALANCE, Treasury Stock, Shares at Sep. 30, 2019							(2,854,755)
BALANCE at Jun. 30, 2019	206,002		$ 329	186,182	132,965			(6,726)
BALANCE, Shares at Jun. 30, 2019			32,871,504
BALANCE, Treasury Stock, Value at Jun. 30, 2019							$ (106,748)
BALANCE, Treasury Stock, Shares at Jun. 30, 2019							(2,854,496)
Net income	21,212				21,212
Surrender of common stock awards, value	(8)						$ (8)
Surrender of common stock awards, shares							(259)
Share-based compensation expense	1,933			1,933
Share-based compensation issued to directors, value	101			101
Other comprehensive income (loss), net of tax	(1,726)							(1,726)
BALANCE at Sep. 30, 2019	227,514		$ 329	188,216	154,177			(8,452)
BALANCE, Shares at Sep. 30, 2019			32,871,504
BALANCE, Treasury Stock, Value at Sep. 30, 2019							$ (106,756)
BALANCE, Treasury Stock, Shares at Sep. 30, 2019							(2,854,755)
BALANCE at Dec. 31, 2019	$ 250,031	$ (1,190)	$ 329	190,230	173,371	$ (1,190)		(7,143)
BALANCE, Shares at Dec. 31, 2019	32,871,504		32,871,504
BALANCE, Treasury Stock, Value at Dec. 31, 2019	$ (106,756)						$ (106,756)
BALANCE, Treasury Stock, Shares at Dec. 31, 2019	(2,855,164)						(2,855,164)
Net income	$ 69,402				69,402
Issuance of common stock awards to employees, value			$ 2	(2)
Issuance of common stock awards to employees, shares			249,435
Surrender of common stock awards, value	(973)						$ (973)
Surrender of common stock awards, shares							(29,069)
Share-based compensation expense	7,029			7,029
Share-based compensation issued to directors, value	229			229
Share-based compensation issued to directors, shares			6,371
Common stock repurchase, value	(15,759)						$ (15,759)
Common stock repurchase, shares							(442,542)
Other comprehensive income (loss), net of tax	(4,582)							(4,582)
BALANCE at Sep. 30, 2020	$ 304,187		$ 331	197,486	241,583			(11,725)
BALANCE, Shares at Sep. 30, 2020	33,127,310		33,127,310
BALANCE, Treasury Stock, Value at Sep. 30, 2020	$ (123,488)						$ (123,488)
BALANCE, Treasury Stock, Shares at Sep. 30, 2020	(3,326,775)						(3,326,775)
BALANCE at Jun. 30, 2020	$ 272,736		$ 331	195,288	213,506			(12,901)
BALANCE, Shares at Jun. 30, 2020			33,124,237
BALANCE, Treasury Stock, Value at Jun. 30, 2020							$ (123,488)
BALANCE, Treasury Stock, Shares at Jun. 30, 2020							(3,325,049)
Net income	28,077				28,077
Issuance of common stock awards to employees, shares			3,073
Surrender of common stock awards, shares							(1,726)
Share-based compensation expense	2,094			2,094
Share-based compensation issued to directors, value	104			104
Other comprehensive income (loss), net of tax	1,176							1,176
BALANCE at Sep. 30, 2020	$ 304,187		$ 331	$ 197,486	$ 241,583			$ (11,725)
BALANCE, Shares at Sep. 30, 2020	33,127,310		33,127,310
BALANCE, Treasury Stock, Value at Sep. 30, 2020	$ (123,488)						$ (123,488)
BALANCE, Treasury Stock, Shares at Sep. 30, 2020	(3,326,775)						(3,326,775)