Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule Of Income Taxes [Line Items]
Effective income tax rate	21.00%	21.00%	35.00%
Net foreign operating loss carry-forward	$ 89,200
Valuation allowance recognized	54,610	$ 50,628
Net change in valuation allowance	4,000	(11,800)
Net deferred tax assets	375,935	110,867
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	754,800
Federal net operating loss carry-forward	754,800
Net state operating tax loss carry-forward	413,700
Deferred foreign withholding taxes	7,706	6,225
GILTI provisional amounts	18,150	$ 13,756	$ 11,681
Real Estate Investment Trust [Member]
Schedule Of Income Taxes [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	652,900
Federal net operating loss carry-forward	652,900
Expire Between 2025 and 2037 [Member]
Schedule Of Income Taxes [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	747,000
Federal net operating loss carry-forward	747,000
Indefinite Carry-forward [Member]
Schedule Of Income Taxes [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Domestic	7,800
Federal net operating loss carry-forward	$ 7,800
Minimum [Member]
Schedule Of Income Taxes [Line Items]
Operating loss carry-forward, expiration year	2025
Foreign and state operating tax loss carry forwards expiration date	2020
Maximum [Member]
Schedule Of Income Taxes [Line Items]
Operating loss carry-forward, expiration year	2037