Summary of Significant Accounting Policies (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Jan. 01, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Cumulative effect of new accounting pronouncement
Trade accounts receivable and contract assets, net		$ 190,950			$ 196,629
Other current assets, net		192,724			179,531
Other investments, net		284,238			325,405
Other non-current assets, net		344,569			334,841
Total assets		7,025,536			7,154,298
Deferred tax liabilities, net		352,948			351,692
Accumulated earnings		583,474			632,809
Non-controlling interests		58,574			75,748
Total stockholders’ equity		3,613,136	$ 3,584,268		3,745,553	$ 3,683,915	$ 4,242,951	$ 4,155,474
Total liabilities and stockholders’ equity		7,025,536			7,154,298
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member
Accumulated Earnings (Losses)
Cumulative effect of new accounting pronouncement
Total stockholders’ equity		$ 583,474	$ 558,034		632,809	$ 685,927	$ 704,236	$ 694,129
Adoption of ASC 326 Increase (Decrease)
Cumulative effect of new accounting pronouncement
Trade accounts receivable and contract assets, net				$ (13,672)
Other current assets, net				6,723
Other investments, net				(7,381)
Other non-current assets, net				4,050
Total assets				(10,280)
Deferred tax liabilities, net				(972)
Accumulated earnings				(9,068)
Non-controlling interests				(240)
Total stockholders’ equity				(9,308)	(9,308)
Total liabilities and stockholders’ equity				(10,280)
Adoption of ASC 326 Increase (Decrease) | Accumulated Earnings (Losses)
Cumulative effect of new accounting pronouncement
Total stockholders’ equity					(9,068)
Balance at January 1, 2020
Cumulative effect of new accounting pronouncement
Trade accounts receivable and contract assets, net				182,957
Other current assets, net				186,254
Other investments, net				318,024
Other non-current assets, net				338,891
Total assets				7,144,018
Deferred tax liabilities, net				350,720
Accumulated earnings				623,741
Non-controlling interests				75,508
Total stockholders’ equity				3,736,245	3,736,245
Total liabilities and stockholders’ equity				$ 7,144,018
Balance at January 1, 2020 | Accumulated Earnings (Losses)
Cumulative effect of new accounting pronouncement
Total stockholders’ equity					$ 623,741