Income Taxes (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes [Line Items]
Unrecognized tax benefits	$ 17,383,000	$ 17,792,000
Corporate federal income tax rate	21.00%
Federal [Member]
Income Taxes [Line Items]
Change in operating loss carryforward	$ 12,892,000
Operating loss carryforwards	23,727,000
Operating loss carryforwards, valuation allowance	0
Unrecognized tax benefits	68,923,000
Deferred tax assets, operating loss carryforwards	92,650,000
State [Member]
Income Taxes [Line Items]
Change in operating loss carryforward	80,966,000
Operating loss carryforwards	731,252,000
Unrecognized tax benefits	85,645,000
Deferred tax assets, operating loss carryforwards	$ 816,897,000
Minimum [Member] | State [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration dates	2023
Maximum [Member] | Federal [Member]
Income Taxes [Line Items]
Operating loss carryforwards, expiration dates	2032
Pennsylvania [Member]
Income Taxes [Line Items]
Unrecognized tax benefits that would impact effective tax rate	$ 28,886,000
Deferred income tax liabilities			$ 175,108,000