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3. Cash, Cash Equivalents, and Marketable Securities (Details) - Cash, Cash Equivalents, and Marketable Securities - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Cash, Cash Equivalents, and Marketable Securities [Line Items]
Cash and cash equivalents	$ 929,355	$ 1,352,741
Marketable securities	579,340	811,506
Total cash, cash equivalents, and marketable securities	1,508,695	2,164,247
Restricted cash - current	47,915	13,697
Restricted cash - noncurrent	41,608	80,072
Cash, cash equivalents, and restricted cash	1,018,878	1,446,510	$ 1,206,625	$ 1,562,623
Marketable Securities, Sale Proceeds	130,800
Maximum [Member]
Cash, Cash Equivalents, and Marketable Securities [Line Items]
Marketable Securities, Realized Loss	100
Foreign debt [Member]
Cash, Cash Equivalents, and Marketable Securities [Line Items]
Marketable securities	292,569	387,820
Foreign government obligations [Member]
Cash, Cash Equivalents, and Marketable Securities [Line Items]
Marketable securities	0	22,011
U.S debt [Member]
Cash, Cash Equivalents, and Marketable Securities [Line Items]
Marketable securities	54,567	66,134
Time deposits [Member]
Cash, Cash Equivalents, and Marketable Securities [Line Items]
Marketable securities	232,204	335,541
Cash [Member]
Cash, Cash Equivalents, and Marketable Securities [Line Items]
Cash and cash equivalents	929,014	1,345,419
Money Market Funds [Member]
Cash, Cash Equivalents, and Marketable Securities [Line Items]
Cash and cash equivalents	$ 341	$ 7,322