Income Tax (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Foreign	$ 27,800	$ 152,000
Valuation Allowance Related To Tax Cuts And Jobs Act Of 2017	58,900
Foreign Currency Translation Adjustment On Valuation Allowance	(12,800)	10,600
Reclassification With Other Deferred Tax Assets Impact on Valuation Allowance		(5,600)
Cash paid for income taxes	144,100	48,700	$ 68,000
Tax Adjustments, Settlements, and Unusual Provisions	(62,173)	(1,033,755)	0
Deferred Tax Assets, Valuation Allowance	181,110	226,884
Proceeds from Income Tax Refunds	2,400	11,600	6,900
Deferred Tax Liability Not Recognized, Amount of Unrecognized Deferred Tax Liability	1,364,100	1,442,900
Tax Credit Carryforward, Valuation Allowance	65,100
Subsidiary Net Operating Loss	24,500
Operating Loss Carryforwards	1,733
Unrecognized Tax Benefits	324,625	321,224	297,290	$ 296,213
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	12,800
Unrecognized Tax Benefits, Interest on Income Taxes Expense	3,300	5,000	$ 8,400
Income Tax Examination, Penalties Expense		300
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	$ 11,600	15,100
Foreign Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Foreign		3,300
Foreign Tax Authority [Member] | Australian Taxation Office [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Foreign		20,100
Foreign Tax Authority [Member] | Revenue Commissioners, Ireland [Member]
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Tax Credit Carryforwards, Foreign		$ 65,100