CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-In Capital	Accumulated Surplus	Accumulated Other Comprehensive Income (Loss)	Total
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect adjustment for adoption of new ASU			$ 4		$ 4
BALANCE at Dec. 31, 2018	$ 114	$ 150,905	81,354	$ (4,810)	227,563
BALANCE at Dec. 31, 2018	114	150,905	81,358	(4,810)	227,567
Components of comprehensive income:
Net income			8,660		8,660
Foreign currency translation adjustments				277	277
COMPREHENSIVE INCOME			8,660	277	8,937
Issuance of common stock to non-employee directors		150			150
Dividends paid			(2,052)		(2,052)
BALANCE at Mar. 31, 2019	114	151,055	87,966	(4,533)	234,602
BALANCE at Dec. 31, 2019					257,927
BALANCE at Dec. 31, 2019	114	151,055	112,261	(5,503)	257,927
Components of comprehensive income:
Net income			5,431		5,431
Foreign currency translation adjustments				(72)	(72)
COMPREHENSIVE INCOME			5,431	(72)	5,359
Issuance of common stock to non-employee directors		194			194
Dividends paid			(2,053)		(2,053)
BALANCE at Mar. 31, 2020	$ 114	$ 151,249	$ 115,639	$ (5,575)	$ 261,427