Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Schedule Of Income Taxes [Line Items]
Income tax expense due to re-measurement of deferred tax assets and liabilities as result of changes in federal tax rate		$ 13,400
Income tax benefit	$ 3,000
Valuation allowance related to gross deferred tax assets			$ 5,134	$ 4,573
Deferred tax assets, net operating loss carry forwards			$ 51,400
Minimum
Schedule Of Income Taxes [Line Items]
Deferred tax assets, net operating loss carry forwards, expiration date			2020
Maximum
Schedule Of Income Taxes [Line Items]
Deferred tax assets, net operating loss carry forwards, expiration date			2040
PENNSYLVANIA
Schedule Of Income Taxes [Line Items]
Valuation allowance related to gross deferred tax assets			$ 5,100	$ 4,600