CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY - USD ($) $ in Thousands	Total	Class A Common Stock	Common Stock Class A Common Stock	Common Stock Class B Common Stock	Treasury Stock	Additional Paid-In Capital	Retained Earnings
Beginning balance (in shares) at Dec. 31, 2018			12,995,080	3,560,604	0
Beginning balance at Dec. 31, 2018	$ 389,829		$ 0	$ 0	$ 0	$ 328,404	$ 61,425
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	451						451
Shares returned in lieu of tax payments (in shares)					34,704
Shares returned in lieu of tax payments	(633)				$ (633)
Conversion of Class B Common Stock (in shares)			751,633	(751,633)
Exercise of warrants (in shares)			177,186
Issuance of common stock (in shares)			68,246	3,035
Stock-based compensation expense	1,208					1,208
Ending balance (in shares) at Mar. 31, 2019			13,992,145	2,812,006	34,704
Ending balance at Mar. 31, 2019	390,855		$ 0	$ 0	$ (633)	329,612	61,876
Beginning balance (in shares) at Dec. 31, 2018			12,995,080	3,560,604	0
Beginning balance at Dec. 31, 2018	389,829		$ 0	$ 0	$ 0	328,404	61,425
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	59,635
Ending balance (in shares) at Sep. 30, 2019			15,483,235	2,048,108	67,833
Ending balance at Sep. 30, 2019	452,114		$ 0	$ 0	$ (1,156)	332,210	121,060
Beginning balance (in shares) at Mar. 31, 2019			13,992,145	2,812,006	34,704
Beginning balance at Mar. 31, 2019	390,855		$ 0	$ 0	$ (633)	329,612	61,876
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	42,861						42,861
Shares returned in lieu of tax payments (in shares)					33,129
Shares returned in lieu of tax payments	(523)				$ (523)
Conversion of Class B Common Stock (in shares)			115,153	(115,153)
Exercise of warrants (in shares)			170,659
Issuance of common stock (in shares)			50,581
Stock-based compensation expense	1,106					1,106
Ending balance (in shares) at Jun. 30, 2019			14,328,538	2,696,853	67,833
Ending balance at Jun. 30, 2019	434,299		$ 0	$ 0	$ (1,156)	330,718	104,737
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	16,323						16,323
Conversion of Class B Common Stock (in shares)			648,745	(648,745)
Exercise of warrants (in shares)			494,929
Issuance of common stock (in shares)			11,023
Stock-based compensation expense	1,492					1,492
Ending balance (in shares) at Sep. 30, 2019			15,483,235	2,048,108	67,833
Ending balance at Sep. 30, 2019	452,114		$ 0	$ 0	$ (1,156)	332,210	121,060
Beginning balance (in shares) at Dec. 31, 2019			15,681,439	1,926,848	68,658
Beginning balance at Dec. 31, 2019	455,216		$ 0	$ 0	$ (1,171)	333,705	122,682
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(7,351)						(7,351)
Shares returned in lieu of tax payments (in shares)					75,493
Shares returned in lieu of tax payments	(1,072)				$ (1,072)
Conversion of Class B Common Stock (in shares)			38,563	(38,563)
Exercise of warrants (in shares)			121,114
Issuance of common stock (in shares)			112,569
Stock-based compensation expense	719					719
Ending balance (in shares) at Mar. 31, 2020			15,953,685	1,888,285	144,151
Ending balance at Mar. 31, 2020	447,512		$ 0	$ 0	$ (2,243)	334,424	115,331
Beginning balance (in shares) at Dec. 31, 2019			15,681,439	1,926,848	68,658
Beginning balance at Dec. 31, 2019	455,216		$ 0	$ 0	$ (1,171)	333,705	122,682
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(59,470)
Ending balance (in shares) at Sep. 30, 2020		17,930,745	17,930,745	2,416,253	174,222
Ending balance at Sep. 30, 2020	397,068		$ 0	$ 0	$ (2,414)	336,270	63,212
Beginning balance (in shares) at Mar. 31, 2020			15,953,685	1,888,285	144,151
Beginning balance at Mar. 31, 2020	447,512		$ 0	$ 0	$ (2,243)	334,424	115,331
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(36,316)						(36,316)
Shares returned in lieu of tax payments (in shares)					30,071
Shares returned in lieu of tax payments	(171)				$ (171)
Exercise of warrants (in shares)			1,723,253	686,315
Issuance of common stock (in shares)			66,476
Stock-based compensation expense	985					985
Ending balance (in shares) at Jun. 30, 2020			17,743,414	2,574,600	174,222
Ending balance at Jun. 30, 2020	412,010		$ 0	$ 0	$ (2,414)	335,409	79,015
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(15,803)						(15,803)
Conversion of Class B Common Stock (in shares)			158,347	(158,347)
Issuance of common stock (in shares)			28,984
Stock-based compensation expense	861					861
Ending balance (in shares) at Sep. 30, 2020		17,930,745	17,930,745	2,416,253	174,222
Ending balance at Sep. 30, 2020	$ 397,068		$ 0	$ 0	$ (2,414)	$ 336,270	$ 63,212