CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings	Total
BALANCE at Dec. 31, 2017	$ 411	$ (63,519)	$ 312,784	$ 168,269	$ 417,945
BALANCE (in shares) at Dec. 31, 2017	41,123,365
BALANCE (in shares) at Dec. 31, 2017		(3,936,291)
Increase (Decrease) in Stockholders' Equity
Net income				16,659	16,659
Issuance of Stock:
Issuance of shares for options exercised		$ 326	(88)		238
Issuance of shares for options exercised (in shares)		19,124
Issuance of restricted stock & performance stock		$ 892	1,331		2,223
Issuance of restricted stock & performance stock (in shares)		52,306
Shares received in lieu of tax withholding payment on vested restricted stock		$ (846)			(846)
Shares received in lieu of tax withholding payment on vested restricted stock (in shares)		(19,921)
Stock-based compensation			1,880		1,880
Dividends				(2,786)	(2,786)
Share repurchase		$ (6,175)			(6,175)
Share repurchase (in shares)		(150,481)
BALANCE at Mar. 31, 2018	$ 411	$ (69,322)	315,907	182,142	429,138
BALANCE (in shares) at Mar. 31, 2018	41,123,365
BALANCE (in shares) at Mar. 31, 2018		(4,035,263)
BALANCE at Dec. 31, 2018	$ 411	$ (87,747)	316,479	268,904	$ 498,047
BALANCE (in shares) at Dec. 31, 2018	41,123,365				41,123,365
BALANCE (in shares) at Dec. 31, 2018		(4,229,653)			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				41,123,365
BALANCE (in shares) at Mar. 31, 2019		(4,232,418)			4,232,418