Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
(Benefit) provision for income taxes	$ 16,066	$ 66,636	$ 47,375	$ 89,608
Effective income tax rate	23.70%	90.20%	19.90%	16.70%
Discrete tax provision	$ 55,200		$ 55,200
Income tax provision, remeasurement of deferred taxes						$ 126,500
Income tax provision, adjustment to AMT credit			$ 300
Alternative Minimum Tax Credit
Operating Loss Carryforwards [Line Items]
Provisional income tax benefit						$ 4,900
New Jersey Division of Taxation | Scenario, Forecast
Operating Loss Carryforwards [Line Items]
Increase in income tax benefit from continuing operations					$ 3,600
Increase in income tax provision for discontinued operations					$ 3,600