Income Taxes - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Valuation Allowance [Line Items]
Computed at federal statutory rate	21.00%	21.00%	21.00%
Income taxes receivable	$ 0	$ 1,236,000	$ 2,500,000
Deferred State and Local Income Tax Expense (Benefit)	(2,660,000)	2,137,000	523,000
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount	1,192,000	(389,000)	285,000
Liabilities for unrecognized tax benefits	0	0
Deferred Tax Assets, Valuation Allowance	179,006,000	114,939,000
Income Tax Examination, Penalties and Interest Expense	$ 0	$ 0	$ 0
Effective Income Tax Rate Reconciliation, Percent	(0.70%)	3.00%	0.20%
Deferred Federal Income Tax Expense (Benefit)	$ 1,236,000	$ 1,236,000	$ 2,471,000
Federal	(1,236,000)	(1,236,000)	$ (2,471,000)
Deferred income taxes	0	1,424,000
Deferred Tax and Other Liabilities, Noncurrent	8,266,000	$ 83,330,000
Federal
Valuation Allowance [Line Items]
Operating Loss Carryforwards	638,600,000
Federal, State and Local Tax Jurisdictions
Valuation Allowance [Line Items]
Deferred Tax Assets, Valuation Allowance	$ 179,000,000.0