Intangible Assets (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 1,339		$ 1,339		$ 1,353
Accumulated Amortization	(1,036)		(1,036)		(713)
Net	303		$ 303		$ 640
Remaining Useful Life (Years)			3 years 6 months		2 years 9 months 18 days
Amortization of intangible assets	100	$ 100	$ 300	$ 300
Disposal permits
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	540		540		$ 554
Accumulated Amortization	(326)		(326)		(269)
Net	214		$ 214		$ 285
Remaining Useful Life (Years)			4 years 10 months 24 days		5 years
Trade name
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	799		$ 799		$ 799
Accumulated Amortization	(710)		(710)		(444)
Net	$ 89		$ 89		$ 355
Remaining Useful Life (Years)			3 months 18 days		1 year