CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2019	$ 33	$ 17,033	$ 362,515	$ (204)	$ (324,660)	$ 54,717
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	11,245	0	0	11,245
Foreign currency translation	0	0	0	(61)	0	(61)
Dividends declared	0	0	(552)	0	0	(552)
Stock based compensation expense	0	941	0	0	0	941
Purchase of treasury stock	0	0	0	0	(946)	(946)
Balance at Mar. 31, 2020	33	17,974	373,208	(265)	(325,606)	65,344
Balance at Dec. 31, 2019	33	17,033	362,515	(204)	(324,660)	54,717
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income						38,970
Foreign currency translation						(23)
Balance at Sep. 30, 2020	33	20,104	399,835	(227)	(328,015)	91,730
Balance at Mar. 31, 2020	33	17,974	373,208	(265)	(325,606)	65,344
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	11,290	0	0	11,290
Foreign currency translation	0	0	0	(4)	0	(4)
Dividends declared	0	0	(551)	0	0	(551)
Stock based compensation expense	0	1,137	0	0	0	1,137
Purchase of treasury stock	0	0	0	0	(772)	(772)
Balance at Jun. 30, 2020	33	19,111	383,947	(269)	(326,378)	76,444
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	16,435	0	0	16,435
Foreign currency translation	0	0	0	42	0	42
Dividends declared	0	0	(547)	0	0	(547)
Stock based compensation expense	0	993	0	0	0	993
Purchase of treasury stock	0	0	0	0	(1,637)	(1,637)
Balance at Sep. 30, 2020	33	20,104	399,835	(227)	(328,015)	91,730
Balance at Dec. 31, 2020	33	21,219	394,386	(165)	(328,562)	86,911
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	15,950	0	0	15,950
Foreign currency translation	0	0	0	10	0	10
Dividends declared	0	0	(548)	0	0	(548)
Stock based compensation expense	0	1,166	0	0	0	1,166
Purchase of treasury stock	0	0	0	0	(1,814)	(1,814)
Balance at Mar. 31, 2021	33	22,385	409,788	(155)	(330,376)	101,675
Balance at Dec. 31, 2020	33	21,219	394,386	(165)	(328,562)	86,911
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income						62,212
Foreign currency translation						(16)
Balance at Sep. 30, 2021	33	24,241	400,452	(181)	(336,360)	88,185
Balance at Mar. 31, 2021	33	22,385	409,788	(155)	(330,376)	101,675
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	17,101	0	0	17,101
Foreign currency translation	0	0	0	5	0	5
Dividends declared	0	0	(55,061)	0	0	(55,061)
Stock based compensation expense	0	946	0	0	0	946
Purchase of treasury stock	0	0	0	0	(3,520)	(3,520)
Balance at Jun. 30, 2021	33	23,331	371,828	(150)	(333,896)	61,146
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	29,161	0	0	29,161
Foreign currency translation	0	0	0	(31)	0	(31)
Dividends declared	0	0	(537)	0	0	(537)
Stock based compensation expense	0	910	0	0	0	910
Purchase of treasury stock	0	0	0	0	(2,464)	(2,464)
Balance at Sep. 30, 2021	$ 33	$ 24,241	$ 400,452	$ (181)	$ (336,360)	$ 88,185