Income Taxes Income Taxes Details 3 (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
Income Taxes [Abstract]
Computed tax provision at the applicable federal statutory income tax rate									$ 92,764	$ 140,090	$ 114,331
State and local taxes, net of federal income tax benefits									10,146	8,216	13,279
Foreign jurisdiction differences									2,377	(6,782)	(2,557)
Permanent differences associated with dispositions									790	1,925	9,267
Changes in uncertain tax positions									(88,687)	(105,821)	5,669
Foreign Valuation Allowance, Amount									(431)	1,186	15,850
Enactment of US Tax Reform									(16,105)	(146,160)	0
Excess tax benefit from share-based compensation									(11,159)	(18,521)	0
Other									4,479	(20,722)	(6,486)
Provision for income taxes	$ 67,224	$ (17,043)	$ (16,034)	$ (28,321)	$ 113,759	$ (10,437)	$ (32,956)	$ 76,223	$ (5,826)	$ (146,589)	$ 149,353
Total effective tax rate									(1.30%)	(36.60%)	45.70%