Related Party Transactions (Summarized Financial Information of Company's Equity Method Investees) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Related Party Transaction [Line Items]
Revenues	$ 8,208,436	$ 8,170,191	$ 3,045,382
Gross profit	404,922	517,892	302,005
Net income (loss)	(14,215)	15,060	41,225
Current assets	2,416,409	1,945,342
Current liabilities	1,931,682	1,439,919
Noncontrolling interests	1,160,660	1,195,655	876,764	$ 822,899
Subsidiaries
Related Party Transaction [Line Items]
Revenues	1,625,686	1,930,289	6,111,036
Gross profit	32,467	39,253	257,594
Income from continuing operations	3,315	1,895	71,608
Net income (loss)	2,777	940	68,876
Current assets	370,190	255,052	1,111,826
Non-current assets	89,456	80,823	526,169
Current liabilities	296,074	196,163	792,184
Non-current liabilities	$ 40,077	$ 31,509	$ 281,103