CONDENSED CONSOLIDATED STATEMENTS OF EQUITY UNAUDITED - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]	Treasury Stock [Member]	Total
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASU | ASU 2016-01 [Member]	$ 0	$ 0	$ (106)	$ 0	$ 0	$ (106)
Balance at Dec. 31, 2018	33	14,192	282,928	(240)	(287,303)	9,610
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	19,892	0	0	19,892
Foreign currency translation gain / (loss)	0	0	0	20	0	20
Dividends declared	0	0	(575)	0	0	(575)
Stock based compensation expense	0	577	0	0	0	577
Purchase of treasury stock	0	0	0	0	(2,547)	(2,547)
Balance at Mar. 31, 2019	33	14,769	302,139	(220)	(289,850)	26,871
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 gain / (loss)	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