Unaudited Condensed Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands		Total	Preferred Stock Conversion Agreement	Common Stock	Common Stock Preferred Stock Conversion Agreement	Additional Paid-in Capital	Additional Paid-in Capital Preferred Stock Conversion Agreement	Retained Earnings	Retained Earnings Preferred Stock Conversion Agreement	Treasury Stock
Beginning Balance (in shares) at Dec. 31, 2018				17,784,769						4,970,093
Beginning Balance at Dec. 31, 2018		$ 310,998		$ 18		$ 334,744		$ 187,127		$ (210,891)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		582						582
Stock-based compensation		2,103				2,103
Exercise of employee stock options (in shares)				57,022						0
Exercise of employee stock options		2,557		$ 0		2,557				$ 0
Restricted stock issued (in shares)				25,357						3,459
Restricted stock issued		(217)								$ (217)
Shares issued for bonus settlement and director stipends (in shares)				599
Shares issued for bonus settlement and director stipends		0				0
Convertible preferred stock dividends	[1]	(1,087)						(1,087)
Ending Balance (in shares) at Mar. 31, 2019				17,867,747						4,973,552
Ending Balance at Mar. 31, 2019		314,936		$ 18		339,404		186,622		$ (211,108)
Beginning Balance (in shares) at Dec. 31, 2018				17,784,769						4,970,093
Beginning Balance at Dec. 31, 2018		310,998		$ 18		334,744		187,127		$ (210,891)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(1,129)
Ending Balance (in shares) at Jun. 30, 2019				17,947,072						4,975,971
Ending Balance at Jun. 30, 2019		317,243		$ 18		344,676		183,812		$ (211,263)
Beginning Balance (in shares) at Mar. 31, 2019				17,867,747						4,973,552
Beginning Balance at Mar. 31, 2019		314,936		$ 18		339,404		186,622		$ (211,108)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		(1,712)						(1,712)
Stock-based compensation		1,289				1,289
Exercise of employee stock options (in shares)				67,931						0
Exercise of employee stock options		3,826		$ 0		3,826				$ 0
Restricted stock issued (in shares)				7,088						2,419
Restricted stock issued		(155)				0				$ (155)
Shares issued for bonus settlement and director stipends (in shares)				202
Shares issued for bonus settlement and director stipends		0				0
Conversion of convertible preferred stock to common stock (in shares)				4,104
Conversion of convertible preferred stock to common stock		157				157
Convertible preferred stock dividends	[1]	(1,098)						(1,098)
Ending Balance (in shares) at Jun. 30, 2019				17,947,072						4,975,971
Ending Balance at Jun. 30, 2019		317,243		$ 18		344,676		183,812		$ (211,263)
Beginning Balance (in shares) at Dec. 31, 2019				18,073,763						5,088,782
Beginning Balance at Dec. 31, 2019		317,592		$ 18		351,529		183,733		$ (217,688)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		16,098						16,098
Stock-based compensation		1,005				1,005
Exercise of employee stock options (in shares)				39,111
Exercise of employee stock options		2,054				2,054
Restricted stock issued (in shares)				79,029						626
Restricted stock issued		(37)								$ (37)
Shares issued for bonus settlement and director stipends (in shares)				701
Shares issued for bonus settlement and director stipends		38				38
Stock repurchase plan (in shares)										142,821
Stock repurchase plan		$ (7,299)								$ (7,299)
Conversion of convertible preferred stock to common stock (in shares)		40
Conversion of convertible preferred stock to common stock		$ 2				2
Convertible preferred stock dividends	[2]	(1,095)						(1,095)
Ending Balance (in shares) at Mar. 31, 2020				18,192,644						5,232,229
Ending Balance at Mar. 31, 2020		328,358		$ 18		354,628		198,736		$ (225,024)
Beginning Balance (in shares) at Dec. 31, 2019				18,073,763						5,088,782
Beginning Balance at Dec. 31, 2019		317,592		$ 18		351,529		183,733		$ (217,688)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		53,096
Ending Balance (in shares) at Jun. 30, 2020				19,254,090						5,285,085
Ending Balance at Jun. 30, 2020		360,458		$ 19		402,433		185,917		$ (227,911)
Beginning Balance (in shares) at Mar. 31, 2020				18,192,644						5,232,229
Beginning Balance at Mar. 31, 2020		328,358		$ 18		354,628		198,736		$ (225,024)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)		36,998						36,998
Stock-based compensation		691				691
Exercise of employee stock options (in shares)				129,722
Exercise of employee stock options		9,275				9,275
Restricted stock forfeited (in shares)				(8,496)
Shares issued for bonus settlement and director stipends (in shares)				487
Shares issued for bonus settlement and director stipends		38				38
Stock repurchase plan (in shares)										52,856
Stock repurchase plan		(2,887)								$ (2,887)
Conversion of convertible preferred stock to common stock (in shares)				14,166	925,567
Conversion of convertible preferred stock to common stock		546	$ 31,259		$ 1	546	$ 37,255		$ (5,997)
Redemption of convertible preferred stock pursuant to Conversion Agreement			$ (42,954)						$ (42,954)
Convertible preferred stock dividends	[2]	(866)						(866)
Ending Balance (in shares) at Jun. 30, 2020				19,254,090						5,285,085
Ending Balance at Jun. 30, 2020		$ 360,458		$ 19		$ 402,433		$ 185,917		$ (227,911)

[1] Cash dividends on redeemable convertible preferred stock of $1.36 and $1.37 per share were distributed to convertible preferred stockholders for the three months ended March 31, 2019 and June 30, 2019, respectively.

[2] Cash dividends on redeemable convertible preferred stock of $1.37 per share were distributed to convertible preferred stockholders for the three months ended March 31, 2020 and June 30, 2020.