Income Taxes Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Unrecognized Tax Benefits	$ 44,841				$ 95,831				$ 44,841	$ 95,831	$ 85,762	$ 78,079
Unrecognized Tax Benefits, Additions Based on Tax Positions Related to Current Year									0	7,384	3,546
Unrecognized Tax Benefits, Additions for Tax Positions of Prior Years									2,268	2,685	4,706
Unrecognized Tax Benefits, Reductions for Tax Positions of Prior Years									(53,258)	0	(569)
Unrecognized Tax Benefits, Interest on Income Taxes Expense									8,800	6,500	5,700
Income Tax Expense (Benefit)	$ (596)	$ 12,671	$ (1,553)	$ 2,542	$ 35,069	$ (339)	$ 1,524	$ (1,113)	13,064	35,141	3,514
Interest on Prior Year Income Tax Expense [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Income Tax Expense (Benefit)									$ 2,300	$ 800	$ 2,200