Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement of Comprehensive Income [Abstract]
Net income		$ 84,226	$ 89,299	$ 705,054	$ 630,356
Other comprehensive income (loss):
Unrecognized gain (loss) on available-for-sale securities		0	(3,808)	0	(20,285)
Unrealized gains (losses) on cash flow hedges		0	2	0	2
Foreign currency translation gain (loss)		(3,093)	37,343	(36,890)	70,769
Total other comprehensive income (loss)		(3,093)	33,537	(36,890)	50,486
Total comprehensive income (loss)		81,133	122,836	668,164	680,842
Less: Total comprehensive income (loss) attributable to noncontrolling interests(1)	[1]	10,933	14,732	3,675	29,930
Total comprehensive income (loss) attributable to common stockholders		$ 70,200	$ 108,104	$ 664,489	$ 650,912

[1] Includes amounts attributable to redeemable noncontrolling interests.