Basis of Presentation (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019		Mar. 31, 2018	Jan. 01, 2019	Dec. 31, 2018
Basis Of Presentation [Line Items]
Gain (loss) on remeasurement of U.S. dollar denominated intercompany loan	$ (2,100)		$ 1,600
Intercompany foreign currency outstanding balance	471,300				$ 536,900
Right-of-use assets, net	2,552,304	[1]		$ 2,600,000
Current lease liabilities	228,776	[1]		226,000
Long-term lease liabilities	2,282,803	[1]		2,300,000
Rent prepayments and financing lease right-of-use assets included in right-of-use assets				266,300
Cumulative effect of adoption	$ (20,968)			$ (21,000)
Tenant leases, renewal term	5 years
Deferred lease costs	$ 600		2,800
Amortization expense	400		$ 3,100
Unamortized deferred lease costs	$ 4,100				$ 27,000
Minimum [Member]
Basis Of Presentation [Line Items]
Fixed rent escalation	2.00%
Tenant leases, lease term	5 years
Maximum [Member]
Basis Of Presentation [Line Items]
Fixed rent escalation	3.00%
Tenant leases, lease term	10 years

[1] On January 1, 2019, the Company adopted ASU 2016-02 which requires lessees to recognize a right-of-use asset and a lease liability. Upon adoption, certain assets and liabilities were reclassified to Right-of-use assets, net and lease liabilities in accordance with provisions of ASU 2016-02. See Note 1 for further discussion.