Income Taxes - Additional Information (Detail) - USD ($)		3 Months Ended								9 Months Ended	12 Months Ended
	Jan. 01, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Line Items]
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%		35.00%
Income from continuing operations before taxes		$ (46,545,000)	$ (33,153,000)	$ 101,564,000	$ 3,288,000	$ (36,925,000)	$ (11,421,000)	$ 82,783,000	$ 28,670,000	$ 34,400,000	$ 25,154,000	63,107,000	$ 47,276,000
Income Tax Disclosure [Abstract]
Net change in valuation allowance												800,000
Unrecognized income tax benefits						$ 0				$ 0		$ 0
Maximum
Income Tax Disclosure [Abstract]
Net change in valuation allowance											$ 100,000
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	$ 2,500,000
State | Maximum
Income Tax Disclosure [Abstract]
Expiration date of net operating loss carryforward	Dec. 31, 2037
State | Minimum
Income Tax Disclosure [Abstract]
Expiration date of net operating loss carryforward	Dec. 31, 2023
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