Income Taxes - Additional Information (Detail) - USD ($)		3 Months Ended									6 Months Ended	9 Months Ended	12 Months Ended
	Jan. 01, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2020	Sep. 30, 2018	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Income Tax Disclosure [Line Items]
Deferred tax asset		$ 47,806,000				$ 17,262,000					$ 47,806,000		$ 47,806,000	$ 17,262,000
Tax Cuts and Jobs Act, percentage of depreciation for certain fixed assets acquired													100.00%
Tax Cuts and Jobs Act, change in tax rate, discrete tax benefit															$ 11,101,000
Federal statutory tax rate										35.00%		21.00%	21.00%	21.00%
Income from continuing operations before taxes		(44,051,000)	$ (2,051,000)	$ 83,108,000	$ 39,537,000	$ (46,545,000)	$ (33,153,000)	$ 101,564,000	$ 3,288,000	$ 28,700,000		$ 34,400,000	$ 76,543,000	$ 25,154,000	$ 63,107,000
Income Tax Disclosure [Abstract]
Net change in valuation allowance													(100,000)	$ 100,000
Unrecognized income tax benefits		0									0		$ 0
Federal
Income Tax Disclosure [Abstract]
Number of years for examination													4 years
Federal | Tax Year 2017
Income Tax Disclosure [Line Items]
Corporate income tax rate										35.00%
Federal | Tax Year 2018
Income Tax Disclosure [Line Items]
Corporate income tax rate													21.00%
State
Income Tax Disclosure [Abstract]
Net operating loss carry forwards	$ 2,200,000
State | Minimum
Income Tax Disclosure [Abstract]
Expiration date of net operating loss carryforward	Dec. 31, 2023
State | Maximum
Income Tax Disclosure [Abstract]
Expiration date of net operating loss carryforward	Dec. 31, 2037
New York
Income Tax Disclosure [Abstract]
Number of years for examination													4 years
Connecticut
Income Tax Disclosure [Abstract]
Number of years for examination													4 years
Pennsylvania
Income Tax Disclosure [Abstract]
Number of years for examination													4 years
New Jersey
Income Tax Disclosure [Abstract]
Number of years for examination													5 years
CARES Act
Income Tax Disclosure [Line Items]
Deferral payment of social security taxes											6,500,000
Deferred tax asset		$ 900,000									$ 900,000		$ 900,000