Revenue (Breakdown of Revenues by Accounting Standards) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers									$ 1,391,848	$ 898,885
Total Revenues	$ 1,885,603	$ 1,982,755	$ 2,325,041	$ 1,976,792	$ 812,662	$ 685,579	$ 911,402	$ 635,739	8,170,191	3,045,382	$ 3,686,345
Revenues under ASC 606
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Revenue from contract with customers									1,391,848	898,885
Revenues under ASC 842
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total Revenues									118,411	105,631
Revenues under ASC 815
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Total Revenues									$ 6,659,932	$ 2,040,866