CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Total
BALANCE at Dec. 31, 2018	$ 411	$ (87,747)	$ 316,479	$ 268,904	$ 498,047
BALANCE (in shares) at Dec. 31, 2018	41,123,365
BALANCE (in shares) at Dec. 31, 2018		(4,229,653)
Increase (Decrease) in Stockholders' Equity
Net income				19,866	19,866
Issuance of Stock:
Issuance of shares for options exercised		$ 861	(61)		800
Issuance of shares for options exercised (in shares)		41,103
Issuance of restricted stock & performance stock		$ 817	1,189		2,006
Issuance of restricted stock & performance stock (in shares)		38,539
Shares received in lieu of tax withholding payment on vested restricted stock		$ (781)			(781)
Shares received in lieu of tax withholding payment on vested restricted stock (in shares)		(15,013)
Stock-based compensation			2,084		2,084
Dividends				(3,506)	(3,506)
Share repurchase		$ (3,321)			(3,321)
Share repurchase (in shares)		(67,394)
BALANCE at Mar. 31, 2019	$ 411	$ (90,171)	319,691	285,264	515,195
BALANCE (in shares) at Mar. 31, 2019	41,123,365
BALANCE (in shares) at Mar. 31, 2019		(4,232,418)
BALANCE at Dec. 31, 2019	$ 411	$ (103,960)	320,168	368,685	$ 585,304
BALANCE (in shares) at Dec. 31, 2019	41,123,365				41,123,365
BALANCE (in shares) at Dec. 31, 2019		(4,465,448)			4,465,448
Increase (Decrease) in Stockholders' Equity
Net income				17,716	$ 17,716
Issuance of Stock:
Issuance of restricted stock & performance stock		$ 1,054	801		1,855
Issuance of restricted stock & performance stock (in shares)		43,902
Shares received in lieu of tax withholding payment on vested restricted stock		$ (622)			(622)
Shares received in lieu of tax withholding payment on vested restricted stock (in shares)		(14,722)
Stock-based compensation			2,134		2,134
Dividends				(3,844)	(3,844)
Share repurchase		$ (8,985)			(8,985)
Share repurchase (in shares)		(237,359)
BALANCE at Mar. 31, 2020	$ 411	$ (112,513)	$ 323,103	382,042	$ 593,043
BALANCE (in shares) at Mar. 31, 2020	41,123,365				41,123,365
BALANCE (in shares) at Mar. 31, 2020		(4,673,627)			4,673,627
Increase (Decrease) in Stockholders' Equity
Cumulative-effect adjustment				$ (515)	$ (515)