Income Taxes Reconcililation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of period	$ 37,813	$ 9,103
Increase in unrecognized tax benefits resulting from tax positions taken during current period	0	21,902
Increase in unrecognized tax benefits resulting from tax positions taken during prior periods	2,140	7,474
Reduction in unrecognized tax benefits because of the lapse of the applicable statute of limitations	(8,437)	(666)
Balance at end of period	$ 31,516	$ 37,813