Supplemental Cash Flow Information (Schedule of Cash, Cash Equivalents and Restricted Cash Adjustments) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Net changes in operating assets and liabilities	$ 112,045	$ 126,394
Net cash provided by (used in) operating activities	134,542	165,675
Effect of changes in foreign currency rates on cash	3,336	12,123
Effect of changes in foreign currency rates on cash		12,123
Increase (decrease) in cash	116,791	118,772
Cash and cash equivalents	236,894	294,074	$ 207,867
Total cash, cash equivalents and restricted cash	$ 874,880	412,018	$ 758,089	$ 293,246
As Reported [Member]
Net changes in operating assets and liabilities		94,733
Net cash provided by (used in) operating activities		134,014
Effect of changes in foreign currency rates on cash		8,938
Increase (decrease) in cash		$ 83,926