Consolidated Statement of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings
Stockholders' equity at beginning of period at Dec. 31, 2018	$ 389,932	$ 3	$ (79,571)	$ 348,397	$ 121,102
Shares at beginning of period (in shares) at Dec. 31, 2018		31,345,220	(3,947,460)
Increase in stockholders' equity:
Share compensation expense	2,806			2,806
Exercise of stock options	37	$ 0		37
Exercise of stock options (in shares)		3,000
Common stock issued for vested restricted stock	0	$ 0		0
Common stock issued for vested restricted stock (in shares)		215,071
Common stock issued for vested performance shares	0	$ 0		0
Common stock issued for vested performance shares (in shares)		13,267
Common shares withheld and retired to satisfy employee tax withholding obligations upon vesting of restricted stock	(1,978)	$ 0		(1,978)
Common shares withheld and retired to satisfy employee tax withholding obligations upon vesting of restricted stock (in shares)		(81,936)
Repurchase of convertible notes, net of deferred taxes	36			36
Purchases of treasury stock	(10,629)		$ (10,629)
Purchase of treasury stock (in shares)			(452,350)
Net loss	3,497				3,497
Stockholders' equity at end of period at Mar. 31, 2019	383,700	$ 3	$ (90,199)	349,298	124,599
Shares at end of period (in shares) at Mar. 31, 2019		31,494,622	(4,399,810)
Stockholders' equity at beginning of period at Dec. 31, 2018	389,932	$ 3	$ (79,571)	348,397	121,102
Shares at beginning of period (in shares) at Dec. 31, 2018		31,345,220	(3,947,460)
Increase in stockholders' equity:
Net loss	13,407
Stockholders' equity at end of period at Sep. 30, 2019	383,049	$ 3	$ (105,679)	354,216	134,509
Shares at end of period (in shares) at Sep. 30, 2019		31,502,627	(5,101,583)
Stockholders' equity at beginning of period at Mar. 31, 2019	383,700	$ 3	$ (90,199)	349,298	124,599
Shares at beginning of period (in shares) at Mar. 31, 2019		31,494,622	(4,399,810)
Increase in stockholders' equity:
Share compensation expense	2,425			2,425
Common stock issued for vested restricted stock	0	$ 0		0
Common stock issued for vested restricted stock (in shares)		5,789
Common shares withheld and retired to satisfy employee tax withholding obligations upon vesting of restricted stock	(49)	$ 0		(49)
Common shares withheld and retired to satisfy employee tax withholding obligations upon vesting of restricted stock (in shares)		(2,252)
Repurchase of convertible notes, net of deferred taxes	66			66
Purchases of treasury stock	(15,480)		$ (15,480)
Purchase of treasury stock (in shares)			(701,773)
Net loss	5,067				5,067
Stockholders' equity at end of period at Jun. 30, 2019	375,729	$ 3	$ (105,679)	351,739	129,666
Shares at end of period (in shares) at Jun. 30, 2019		31,498,159	(5,101,583)
Increase in stockholders' equity:
Share compensation expense	2,531			2,531
Exercise of stock options		$ 0		0
Exercise of stock options (in shares)		7,019
Common stock issued for vested restricted stock	0	$ 0		(55)
Common stock issued for vested restricted stock (in shares)		(2,551)
Common shares withheld and retired to satisfy employee tax withholding obligations upon vesting of restricted stock	(55)
Net loss	4,843				4,843
Stockholders' equity at end of period at Sep. 30, 2019	383,049	$ 3	$ (105,679)	354,216	134,509
Shares at end of period (in shares) at Sep. 30, 2019		31,502,627	(5,101,583)
Stockholders' equity at beginning of period at Dec. 31, 2019	383,312	$ 3	$ (109,239)	356,600	135,948
Shares at beginning of period (in shares) at Dec. 31, 2019		31,507,247	(5,277,438)
Increase in stockholders' equity:
Share compensation expense	4,608			4,608
Exercise of stock options	381	$ 0		381
Exercise of stock options (in shares)		32,000
Common stock issued for vested restricted stock	0	$ 0		0
Common stock issued for vested restricted stock (in shares)		247,224
Common shares withheld and retired to satisfy employee tax withholding obligations upon vesting of restricted stock	(1,541)	$ 0		(1,541)
Common shares withheld and retired to satisfy employee tax withholding obligations upon vesting of restricted stock (in shares)		(82,802)
Repurchase of convertible notes, net of deferred taxes	(190)			(190)
Purchases of treasury stock	(9,440)		$ (9,440)
Purchase of treasury stock (in shares)			(489,662)
Net loss	(2,933)				(2,933)
Stockholders' equity at end of period at Mar. 31, 2020	374,197	$ 3	$ (118,679)	359,857	133,015
Shares at end of period (in shares) at Mar. 31, 2020		31,703,669	(5,767,100)
Stockholders' equity at beginning of period at Dec. 31, 2019	383,312	$ 3	$ (109,239)	356,600	135,948
Shares at beginning of period (in shares) at Dec. 31, 2019		31,507,247	(5,277,438)
Increase in stockholders' equity:
Net loss	4,836
Stockholders' equity at end of period at Sep. 30, 2020	386,473	$ 3	$ (118,679)	364,364	140,784
Shares at end of period (in shares) at Sep. 30, 2020		31,718,589	(5,767,100)
Stockholders' equity at beginning of period at Mar. 31, 2020	374,197	$ 3	$ (118,679)	359,857	133,015
Shares at beginning of period (in shares) at Mar. 31, 2020		31,703,669	(5,767,100)
Increase in stockholders' equity:
Share compensation expense	2,319			2,319
Common stock issued for vested restricted stock	0	$ 0		0
Common stock issued for vested restricted stock (in shares)		8,105
Common shares withheld and retired to satisfy employee tax withholding obligations upon vesting of restricted stock	(51)	$ 0		(51)
Common shares withheld and retired to satisfy employee tax withholding obligations upon vesting of restricted stock (in shares)		(2,584)
Net loss	951				951
Stockholders' equity at end of period at Jun. 30, 2020	377,417	$ 3	$ (118,679)	362,126	133,967
Shares at end of period (in shares) at Jun. 30, 2020		31,709,190	(5,767,100)
Increase in stockholders' equity:
Share compensation expense	2,298			2,298
Exercise of stock options	24	$ 0		24
Exercise of stock options (in shares)		2,000
Common stock issued for vested restricted stock	0	$ 0		0
Common stock issued for vested restricted stock (in shares)		10,528
Common shares withheld and retired to satisfy employee tax withholding obligations upon vesting of restricted stock	(84)	$ 0		(84)
Common shares withheld and retired to satisfy employee tax withholding obligations upon vesting of restricted stock (in shares)		(3,129)
Net loss	6,818				6,818
Stockholders' equity at end of period at Sep. 30, 2020	$ 386,473	$ 3	$ (118,679)	$ 364,364	$ 140,784
Shares at end of period (in shares) at Sep. 30, 2020		31,718,589	(5,767,100)