Income Taxes - Tax Cuts and Jobs Act (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Percentage of tax on earnings in the form of cash and cash equivalents		15.50%
Percentage of tax on earnings other than in the form of cash and cash equivalents		8.00%
Accrued income tax liabilities under the transition toll tax		$ 400
Transition toll tax, period		8 years
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		35.00%
Deferred taxes, net		$ 83,148	$ 1,060
Forecast
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%