Other Assets (Equity Method Investee) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets [Abstract]
Current assets	$ 471,428	$ 532,330
Non-current assets	3,826,018	3,673,613
Total assets	4,297,446	4,205,943
Liabilities [Abstract]
Current liabilities	1,064,741	1,152,193
Non- current liabilities	2,217,909	1,974,166
Total liabilities	3,282,650	3,126,359
Equity attributable to:
Noncontrolling interest	1,672	1,753
Income Statement [Abstract]
Total revenues	2,255,352	1,994,014	$ 1,340,662
Total expenses	(1,779,160)	(1,684,276)	(1,078,470)
Net income	$ 476,192	$ 309,738	$ 262,192