CONDENSED CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock Cumulative Effect, Period of Adoption, Adjusted Balance	Common Stock	Additional Paid-In Capital Cumulative Effect, Period of Adoption, Adjusted Balance	Additional Paid-In Capital	Accumulated Surplus Cumulative Effect, Period of Adoption, Adjustment	Accumulated Surplus Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Surplus	Accumulated Other Comprehensive Income (Loss) Cumulative Effect, Period of Adoption, Adjusted Balance	Accumulated Other Comprehensive Income (Loss)	Cumulative Effect, Period of Adoption, Adjustment	Cumulative Effect, Period of Adoption, Adjusted Balance	Total
BALANCE at Dec. 31, 2018	$ 114	$ 114	$ 150,905	$ 150,905	$ 4	$ 81,358	$ 81,354	$ (4,810)	$ (4,810)	$ 4	$ 227,567	$ 227,563
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, 2018	$ 114	114	$ 150,905	150,905	$ 4	$ 81,358	81,354	$ (4,810)	(4,810)	$ 4	$ 227,567	227,563
Components of comprehensive income:
Net income												27,419
Foreign currency translation adjustments												(1,213)
COMPREHENSIVE INCOME												26,206
BALANCE at Sep. 30, 2019		114		151,055			102,621		(6,023)			247,767
BALANCE at Mar. 31, 2019		114		151,055			87,966		(4,533)			234,602
Components of comprehensive income:
Net income							10,683					10,683
Foreign currency translation adjustments									(930)			(930)
COMPREHENSIVE INCOME							10,683		(930)			9,753
Dividends paid							(2,051)					(2,051)
BALANCE at Jun. 30, 2019		114		151,055			96,598		(5,463)			242,304
Components of comprehensive income:
Net income							8,076					8,076
Foreign currency translation adjustments									(560)			(560)
COMPREHENSIVE INCOME							8,076		(560)			7,516
Dividends paid							(2,053)					(2,053)
BALANCE at Sep. 30, 2019		114		151,055			102,621		(6,023)			247,767
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
BALANCE at Dec. 31, 2019		114		151,055			112,261		(5,503)			257,927
Components of comprehensive income:
Net income												17,810
Foreign currency translation adjustments												2,477
COMPREHENSIVE INCOME												20,287
BALANCE at Sep. 30, 2020		114		151,249			123,912		(3,026)			272,249
BALANCE at Mar. 31, 2020		114		151,249			115,639		(5,575)			261,427
Components of comprehensive income:
Net income							5,826					5,826
Foreign currency translation adjustments									(312)			(312)
COMPREHENSIVE INCOME							5,826		(312)			5,514
Dividends paid							(2,053)					(2,053)
BALANCE at Jun. 30, 2020		114		151,249			119,412		(5,887)			264,888
Components of comprehensive income:
Net income							6,553					6,553
Foreign currency translation adjustments									2,861			2,861
COMPREHENSIVE INCOME							6,553		2,861			9,414
Dividends paid							(2,053)					(2,053)
BALANCE at Sep. 30, 2020		$ 114		$ 151,249			$ 123,912		$ (3,026)			$ 272,249