Income Taxes Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Unrecognized Tax Benefits, Interest on Income Taxes Expense									$ 6,500	$ 5,700	$ 3,500
Unrecognized Tax Benefits	$ 95,831				$ 85,762				95,831	85,762	78,079	$ 81,459
Unrecognized Tax Benefits, Additions Based on Tax Positions Related to Current Year									7,384	3,546	3,608
Unrecognized Tax Benefits, Additions for Tax Positions of Prior Years									2,685	4,706	1,570
Unrecognized Tax Benefits, Reductions for Tax Positions of Prior Years									0	(569)	(8,558)
Income Tax Expense (Benefit)	$ 35,069	$ (339)	$ 1,524	$ (1,113)	$ (490)	$ 1,845	$ 1,077	$ 1,082	35,141	3,514	1,200
Interest on Prior Year Income Tax Expense [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Income Tax Expense (Benefit)									$ 800	$ 2,200	$ 400