CONSOLIDATED STATEMENT OF STOCKHOLDERS' EQUITY (DEFICIT) (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Additional Paid-In Capital	Accumulated Deficit	Accumulated other comprehensive loss	Class A Common Stock	Class A Common Stock Common Stock	Class B Common Stock	Class B Common Stock Common Stock
Beginning balance at Dec. 31, 2017	$ (37,862)	$ 356,638	$ (395,107)	$ 184		$ 413		$ 10
Beginning balance (in shares) at Dec. 31, 2017						41,298		988
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	310	306				$ 4
Issuance of Class A common stock (in shares)						402
Stock-based compensation	2,077	2,077
Net income	(3,910)		(3,910)
Hedging activity	568			568
Ending balance at Mar. 31, 2018	(38,817)	359,021	(398,999)	734		$ 417		$ 10
Ending balance (in shares) at Mar. 31, 2018						41,700		988
Beginning balance at Dec. 31, 2017	(37,862)	356,638	(395,107)	184		$ 413		$ 10
Beginning balance (in shares) at Dec. 31, 2017						41,298		988
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	20,096
Hedging activity	1,120
Ending balance at Sep. 30, 2018	(5,279)	367,999	(374,993)	1,286		$ 419		$ 10
Ending balance (in shares) at Sep. 30, 2018					41,932	41,932	988	988
Beginning balance at Mar. 31, 2018	(38,817)	359,021	(398,999)	734		$ 417		$ 10
Beginning balance (in shares) at Mar. 31, 2018						41,700		988
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	361	360				$ 1
Issuance of Class A common stock (in shares)						65
Stock-based compensation	2,121	2,121
Net income	1,704		1,704
Hedging activity	(85)			(85)
Ending balance at Jun. 30, 2018	(34,716)	361,502	(397,295)	649		$ 418		$ 10
Ending balance (in shares) at Jun. 30, 2018						41,765		988
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock - acquisition	4,258	4,257				$ 1
Issuance of Class A common stock - acquisition (in shares)						150
Issuances of Class A common stock	72	72
Issuance of Class A common stock (in shares)						17
Stock-based compensation	2,168	2,168
Net income	22,302		22,302
Hedging activity	637			637
Ending balance at Sep. 30, 2018	(5,279)	367,999	(374,993)	1,286		$ 419		$ 10
Ending balance (in shares) at Sep. 30, 2018					41,932	41,932	988	988
Beginning balance at Dec. 31, 2018	(15,832)	373,716	(388,669)	(1,308)		$ 419		$ 10
Beginning balance (in shares) at Dec. 31, 2018					41,944	41,944	988	988
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of Class A common stock - equity offering	100,446	100,410				$ 36
Issuance of Class A common stock - equity offering (in shares)						3,565
Issuance of Class A common stock - acquisition	0	(1)				$ 1
Issuance of Class A common stock - acquisition (in shares)						67
Issuances of Class A common stock	260	253				$ 7
Issuance of Class A common stock (in shares)						676
Stock-based compensation	1,431	1,431
Net income	(1,714)		(1,714)
Hedging activity	(1,557)			(1,557)
Ending balance at Mar. 31, 2019	83,034	475,809	(390,383)	(2,865)		$ 463		$ 10
Ending balance (in shares) at Mar. 31, 2019						46,252		988
Beginning balance at Dec. 31, 2018	(15,832)	373,716	(388,669)	(1,308)		$ 419		$ 10
Beginning balance (in shares) at Dec. 31, 2018					41,944	41,944	988	988
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	22,587
Hedging activity	(5,263)
Ending balance at Sep. 30, 2019	110,812	482,987	(366,082)	(6,571)		$ 468		$ 10
Ending balance (in shares) at Sep. 30, 2019					46,792	46,792	988	988
Beginning balance at Mar. 31, 2019	83,034	475,809	(390,383)	(2,865)		$ 463		$ 10
Beginning balance (in shares) at Mar. 31, 2019						46,252		988
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	2,318	2,315				$ 3
Issuance of Class A common stock (in shares)						347
Stock-based compensation	1,889	1,889
Net income	11,915		11,915
Hedging activity	(2,959)			(2,959)
Ending balance at Jun. 30, 2019	96,197	480,013	(378,468)	(5,824)		$ 466		$ 10
Ending balance (in shares) at Jun. 30, 2019						46,599		988
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuances of Class A common stock	1,078	1,076				$ 2
Issuance of Class A common stock (in shares)						193
Stock-based compensation	1,898	1,898
Net income	12,386		12,386
Hedging activity	(747)			(747)
Ending balance at Sep. 30, 2019	$ 110,812	$ 482,987	$ (366,082)	$ (6,571)		$ 468		$ 10
Ending balance (in shares) at Sep. 30, 2019					46,792	46,792	988	988